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Sample records for chloride monolithic column

  1. A poly(alkyl methacrylate-divinylbenzene-vinylbenzyl trimethylammonium chloride) monolithic column for solid-phase microextraction.

    PubMed

    Liu, Wan-Ling; Lirio, Stephen; Yang, Yicong; Wu, Lin-Tai; Hsiao, Shu-Ying; Huang, Hsi-Ya

    2015-05-22

    In this study, an organic polymer monolithic columns, which were prepared via in situ polymerization of alkyl methacrylate-ester (AMA), divinylbenzene (DVB) and vinylbenzyl trimethylammonium chloride (VBTA, charged monomer), were developed as adsorbent for solid-phase microextraction (SPME). Different parameters affecting the extraction efficiency for nine (9) non-steroidal anti-inflammatory drugs (NSAIDs) such as the ratio of the stearyl methacrylate (SMA) to DVB monomer, column length, sample pH, extraction flow rate and desorption solvent were investigated to obtain the optimal SPME condition. Also, the permeability for each poly(AMA-DVB-VBTA) monolithic column was investigated by adding porogenic solvent (poly(ethylene glycol), PEG). Using the optimized condition, a series of AMA-based poly(AMA-DVB-VBTA) monolith columns were developed to determine the effect the extraction efficiency of NSAIDs by varying the alkyl chain length of the methacrylate ester (methyl-, butyl-, octyl-, or lauryl-methacrylate; (MMA, BMA, OMA, LMA)). Results showed that decreasing the AMA chain length increases the extraction efficiency of some NSAIDs (i.e. sulindac (sul), naproxen (nap), ketoprofen (ket) and indomethacin (idm)). Among the poly(AMA-DVB-VBTA) monolithic columns, poly(BMA-DVB-VBTA) showed a highly repeatable extraction efficiency for NSAIDs with recoveries ranging from 85.0 to 100.2% with relative standard deviation (RSD) less than 6.8% (n=3). The poly(BMA-DVB-VBTA) can also be reused for at least 50 times without any significant effect in extraction efficiency for NSAIDs. Finally, using the established conditions, the poly(BMA-DVB-VBTA) was used to extract trace-level NSAIDs (100μgL(-1)) in river water with good recoveries ranging from 75.8 to 90.8% (RSD<14.9%).

  2. Characterization of polyacrylamide based monolithic columns.

    PubMed

    Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-01

    Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions.

  3. Characterization of polyacrylamide based monolithic columns.

    PubMed

    Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-01

    Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions. PMID:15354560

  4. Counterflow isotachophoresis in a monolithic column.

    PubMed

    Liu, Bingwen; Cong, Yongzheng; Ivory, Cornelius F

    2014-09-01

    This study describes stationary counterflow isotachophoresis (ITP) in a poly(acrylamide-co-N,N'-methylenebisacrylamide) monolithic column as a means for improving ITP processing capacity and reducing dispersion. The flow profile in the monolith was predicted using COMSOL's Brinkman Equation application mode, which revealed that the flow profile was mainly determined by monolith permeability. As monolith permeability decreases, the flow profile changes from a parabolic shape to a plug shape. An experimental monolithic column was prepared in a fused-silica capillary using an ultraviolet-initiated polymerization method. A monolithic column made from 8% (wt.) monomer was chosen for the stationary counterflow ITP experiments. Counterflow ITP in the monolithic column showed undistorted analyte zones with significantly reduced dispersion compared to the severe dispersion observed in an open capillary. Particularly, for r-phycoerythrin focused by counterflow ITP, its zone width in the monolithic column was only one-third that observed in an open capillary. These experiments demonstrate that stationary counterflow ITP in monoliths can be a robust and practical electrofocusing method.

  5. Synthesis and applications of monolithic HPLC columns

    NASA Astrophysics Data System (ADS)

    Liang, Chengdu

    Silica and carbon monolithic columns were synthesized and modified for liquid chromatography applications. Column configurations and cladding techniques were investigated in detail. Three novel approaches have been developed for the synthesis of bimodal porous rods. Out of these three methods, gel-casting was adopted for the synthesis of silica monoliths with ordered mesopores and uniform macropores; the use of colloidal templates and dual phase separation has been successfully implemented for the synthesis of carbon monoliths with well-controlled meso- and macro- porosities. The formation of mesopores in carbon materials has been further studied in the microphase separation of block copolymers. Electrochemical modification of carbon monoliths was discovered to be an efficient method for converting covalently bonded functionalities to carbon monoliths. N,N'-diethylaminobenzene has been attached to carbon surface for the separation of proteins and protein digests. The performances of carbon-based monolithic columns were studied intensely through frontal analysis and Van Deemter plot. Temperature and pressure effects were also investigated in carbon-based columns. The density of bonding on the modified carbon monoliths was characterized by thermogravimetric analysis.

  6. Exploring the pressure resistance limits of monolithic silica capillary columns.

    PubMed

    Hara, Takeshi; Eeltink, Sebastiaan; Desmet, Gert

    2016-05-13

    We report on an experimental approach to measure the pressure stability and mechanical strength of monolithic silica capillary columns with different diameters (50 and 100μm i.d.) and considering two different domain sizes, typical for the second generation monoliths or smaller. The approach consists of exposing the capillaries to ultra-high pressures (gradually stepwise increased from 20 to 80MPa), with intermediate measurements of the column efficiency, permeability and retention factors to check the mechanical stability of the bed. It was observed that all tested columns withstood the imposed pressure stress, i.e., all the tested parameters remained unaffected up till the maximal test pressure of 80MPa. The applied pressure gradient corresponded to 320MPa/m. The two 100μm i.d.-capillary columns were also exposed to pressures between 80 and 90MPa for a prolonged time (8h), and this did not cause any damage either. PMID:27086284

  7. Cyclodextrin-Functionalized Monolithic Capillary Columns: Preparation and Chiral Applications.

    PubMed

    Adly, Frady G; Antwi, Nana Yaa; Ghanem, Ashraf

    2016-02-01

    In this review, the recently reported approaches for the preparation of cyclodextrin-functionalized capillary monolithic columns are highlighted, with few applications in chiral separations using capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Chirality 28:97-109, 2016. © 2015 Wiley Periodicals, Inc.

  8. Fiber-based monolithic columns for liquid chromatography.

    PubMed

    Ladisch, Michael; Zhang, Leyu

    2016-10-01

    Fiber-based monoliths for use in liquid chromatographic separations are defined by columns packed with aligned fibers, woven matrices, or contiguous fiber structures capable of achieving rapid separations of proteins, macromolecules, and low molecular weight components. A common denominator and motivating driver for this approach, first initiated 25 years ago, was reducing the cost of bioseparations in a manner that also reduced residence time of retained components while achieving a high ratio of mass to momentum transfer. This type of medium, when packed into a liquid chromatography column, minimized the fraction of stagnant liquid and resulted in a constant plate height for non-adsorbing species. The uncoupling of dispersion from eluent flow rate enabled the surface chemistry of the stationary phase to be considered separately from fluid transport phenomena and pointed to new ways to apply chemistry for the engineering of rapid bioseparations. This paper addresses developments and current research on fiber-based monoliths and explains how the various forms of this type of chromatographic stationary phase have potential to provide new tools for analytical and preparative scale separations. The different stationary phases are discussed, and a model that captures the observed constant plate height as a function of mobile phase velocity is reviewed. Methods that enable hydrodynamically stable fiber columns to be packed and operated over a range of mobile phase flow rates, together with the development of new fiber chemistries, are shown to provide columns that extend the versatility of liquid chromatography using monoliths, particularly at the preparative scale. Graphical Abstract Schematic representation of a sample mixture being separated by a rolled-stationary phase column, resulting separated peaks shown in the chromatogram. PMID:27553948

  9. Monolithic molecularly imprinted polymeric capillary columns for isolation of aflatoxins.

    PubMed

    Szumski, Michał; Grzywiński, Damian; Prus, Wojciech; Buszewski, Bogusław

    2014-10-17

    Monolithic molecularly imprinted polymers extraction columns have been prepared in fused-silica capillaries by UV or thermal polymerization in a two-step process. First, a poly-(trimethylolpropane trimethacrylate) (polyTRIM) core monolith was synthesized either by UV or thermal polymerization. Then it was grafted with the mixture of methacrylic acid (MAA) as a functional monomer, ethylene dimethacrylate (EDMA) as a cross-linking agent, 5,7-dimethoxycoumarin (DMC) as an aflatoxin-mimicking template, toluene as a porogen solvent and 2,2-azobis-(2-methylpropionitrile) (AIBN) as an initiator of the polymerization reaction. Different thermal condition of the photografting and different concentrations of the grafting mixture were tested during polymerization. The extraction capillary columns were evaluated in the terms of their hydrodynamic and chromatographic properties. Retention coefficients for aflatoxin B1 and DMC were used for assessment of the selectivity and imprinting factor. The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs. From the MIP columns characterized by the highest permeability the column of the highest imprinting factor was applied for isolation of aflatoxins B1, B2, G1 and G2 from the model aqueous sample followed by on-line chromatographic separation. The process was performed using a micro-MISPE-microLC-LIF system of a novel design, which allowed for detection of the eluates from the sample preparation part as well as from the chromatographic separation.

  10. Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations

    NASA Astrophysics Data System (ADS)

    Ikegami, Tohru; Tanaka, Nobuo

    2016-06-01

    Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics.

  11. Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations.

    PubMed

    Ikegami, Tohru; Tanaka, Nobuo

    2016-06-12

    Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics. PMID:27306311

  12. High efficiency, high temperature separations on silica based monolithic columns.

    PubMed

    Rogeberg, Magnus; Wilson, Steven Ray; Malerod, Helle; Lundanes, Elsa; Tanaka, Nobuo; Greibrokk, Tyge

    2011-10-14

    The effect of temperature on separation using reversed-phase monolithic columns has been investigated using a nano-LC pumping system for gradient separation of tryptic peptides with MS detection. A goal of this study was to find optimal conditions for high-speed separations. The chromatographic performance of the columns was evaluated by peak capacity and peak capacity per time unit. Column lengths ranging from 20 to 100 cm and intermediate gradient times from 10 to 30 min were investigated to assess the potential of these columns in a final step separation, e.g. after fractionation or specific sample preparation. Flow rates from 250 to 2000 nL/min and temperatures from 20 to 120°C were investigated. Temperature had a significant effect on fast separations, and a flow rate of 2000 nL/min and a temperature of 80°C gave the highest peak capacity per time unit. These settings produced 70% more protein identifications in a biological sample compared to a conventional packed column. Alternatively, an equal amount of protein identifications was obtained with a 40% reduction in run time compared to the conventional packed column.

  13. Influence of the crosslinker type on the chromatographic properties of hydrophilic sulfoalkylbetaine-type monolithic columns.

    PubMed

    Liu, Chusheng; Chen, Weijia; Yuan, Guangxin; Xiao, Yao; Crommen, Jacques; Xu, Shihai; Jiang, Zhengjin

    2014-12-19

    In order to investigate the effects of the crosslinker on the separation performance of polar zwitterionic sulfoalkylbetaine-type monolithic columns, three crosslinkers, i.e. 1,4-bis(acryloyl)piperazine (PDA), ethylene dimethacrylate (EDMA) and N,N'-methylenebisacrylamide (MBA), were copolymerized with the hydrophilic monomer N,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPDA). The chromatographic properties of the three hydrophilic sulfoalkylbetaine-type monolithic columns, including column efficiency, permeability, porosity and separation mechanism, were systematically compared using scanning electron microscopy or micro-HPLC. Good selectivity in micro-HPLC separations was achieved on all three monolithic columns. The results indicate that the polarity of sulfoalkylbetaine-type monolithic columns may be related to the polarity of the crosslinker, which further affects column selectivity and efficiency. A particularly high column efficiency (100,000 plates/m) was obtained on the novel poly(SPDA-co-PDA) monolithic column at a linear velocity of 1mm/s using thiourea as test analyte. A higher resolution was also observed for nucleobases, nucleosides and hydrophilic organic acids on this novel poly(SPDA-co-PDA) monolithic column compared to the other two columns. PMID:25464999

  14. Preparation of a biomimetic polyphosphorylcholine monolithic column for immobilized artificial membrane chromatography.

    PubMed

    Zhao, XiangLong; Chen, WeiJia; Zhou, ZhengYin; Wang, QiQin; Liu, ZhengHua; Moaddel, Ruin; Jiang, ZhengJin

    2015-08-14

    The present work aims to prepare a novel phosphatidylcholine functionalized monolithic stationary phase by in situ co-polymerization of 12-methacryloyl dodecylphosphocholine (MDPC) and ethylene dimethacrylate (EDMA) for immobilized artificial membrane chromatography. Scanning electron microscopy, energy dispersive X-ray spectroscopy, FT-IR spectroscopy, pore size distribution analysis, ζ-potential analysis and micro-HPLC were used to evaluate the monolithic structure and physicochemical properties. Satisfactory morphology, high mechanical stability, good permeability and chromatographic performance were obtained on the optimized monolithic columns. A typical reverse-phase retention mechanism was observed over a wide range of organic solvent content (acetonitrile< 80%). The optimized poly(MDPC-co-EDMA) monolith exhibited good selectivity for proteins and basic drugs. Good correlation was observed between the retention on commercial IAM column (IAM.PC.DD2) and poly(MDPC-co-EDMA) monolith. This novel poly(MDPC-co-EDMA) monolith exhibited good potential for studying the drug-membrane interaction.

  15. Hypercrosslinking: New approach to porous polymer monolithic capillary columns with large surface area for the highly efficient separation of small molecules

    PubMed Central

    Urban, Jiri; Svec, Frantisek; Fréchet, Jean M.J.

    2010-01-01

    Monolithic polymers with an unprecedented surface area of over 600 m2/g have been prepared from a poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) precursor monolith that was swollen in 1,2-dichloroethane and hypercrosslinked via Friedel-Crafts reaction catalyzed by ferric chloride. Both the composition of the reaction mixture used for the preparation of the precursor monolith and the conditions of the hypercrosslinking reaction have been varied using mathematical design of experiments and the optimized system validated. Hypercrosslinked monolithic capillary columns contain an array of small pores that make the column ideally suited for the high efficiency isocratic separations of small molecules such as uracil and alkylbenzenes with column efficiencies reproducibly exceeding 60,000 plates/m for retained compounds. The separation process could be accelerated while also improving peak shape through the use of higher temperatures and a ternary mobile phase consisting of acetonitrile, tetrahydrofuran, and water. As a result, seven compounds were well separated in less than 2 min. These columns also facilitate separations of peptide mixtures such as a tryptic digest of cytochrome c using a gradient elution mode which affords a sequence coverage of 93%. A 65 cm long hypercrosslinked capillary column used in size exclusion mode with tetrahydrofuran as the mobile phase afforded almost baseline separation of toluene and five polystyrene standards. PMID:21092973

  16. Fabrication of an ionic liquid-based macroporous polymer monolithic column via atom transfer radical polymerization for the separation of small molecules.

    PubMed

    Zhang, Hang; Bai, Ligai; Wei, Zhen; Liu, Sha; Liu, Haiyan; Yan, Hongyuan

    2016-03-01

    A polymer monolithic column was prepared in a stainless steel column (50×4.6mm i.d.) via atom transfer radical polymerization technique using triallyl isocyanurate and ionic liquid (1-allyl-3-methylimidazolium chloride) as co-monomers, ethylene dimethacrylate as cross linking agent, polyethylene glycol 200, 1,4-butanediol, and N, N- dimethylformamide as porogen system, CCl4 as initiator, and FeCl2 as catalyst. The optimized polymer columns were characterized by scanning electron microscope, nitrogen adsorption-desorption instrument, mercury intrusion porosimetry, infrared spectrometer, and thermogravimetric analysis technique. Respectively, all of these factors above could illustrate that the optimized columns had relative uniform macroporous structure and high thermal stability. A series of basic and acidic small molecules, isomers, and homologues were used to evaluate the performance of these monoliths and enhanced column efficiency was obtained. PMID:26717814

  17. Preparation and characterization of alkyl methacrylate-based monolithic columns for capillary gas chromatography applications.

    PubMed

    Yusuf, Kareem; Aqel, Ahmad; A L Othman, Zeid; Badjah-Hadj-Ahmed, Ahmed Yacine

    2013-08-01

    Gas chromatography (GC) is considered the least common application of both polymer and silica-based monolithic columns. This study describes the fabrication of alkyl methacrylate monolithic materials for use as stationary phases in capillary gas chromatography. Following the deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (TMSM), the monoliths were formed by the co-polymerization of either hexyl methacrylate (HMA) or lauryl methacrylate (LMA) with different percentage of ethylene glycol dimethacrylate (EDMA) in presence of an initiator (azobisisobutyronitrile, AIBN) and a mixture of porogens include 1-propanol, 1,4-butanediol and water. The monoliths were prepared in 500mm length capillaries possessing inner diameters of 250μm. The efficiencies of the monolithic columns for low molecular weight compounds significantly improved as the percentage of crosslinker was increased, because of the greater proportion of pores less than 50nm. The columns containing lower percentages of crosslinker were able to rapidly separate a series of 8 alkane members in 0.7min, but the separation was less efficient for the light alkanes. Columns prepared with the lauryl methacrylate monomer yielded a different morphology for the monolith-interconnected channels. The channels were more branched, which increased the separation time, and unlike the other columns, allowed for temperature programming.

  18. Monolithic column incorporated with lanthanide metal-organic framework for capillary electrochromatography.

    PubMed

    Zhang, Li-Shun; Du, Pei-Yao; Gu, Wen; Zhao, Qing-Li; Huang, Yan-Ping; Liu, Zhao-Sheng

    2016-08-26

    A new lanthanide metal-organic frameworks NKU-1 have successfully incorporated into poly (BMA-co-EDMA) monolith and evaluated by capillary electrochromatography (CEC). Lanthanide metal-organic frameworks [Eu2(ABTC)1.5(H2O)3(DMA)] (NKU-1) were synthesized by self-assembly of Eu(III) ions and 3,3',5,5'-azo benzene tetracarboxylic acid ligands have been fabricated into poly(BMA-co-EDMA) monoliths. 1-Butyl-3-methylimidazolium tetrafluoroborate and N,N-dimethylformamide were developed as binary porogen obtaining homogeneous dispersibility for NKU-1 and high permeability for monolithic column. The successful incorporation of NKU-1 into poly(BMA-co-EDMA) was confirmed and characterized by FT-IR spectra, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer area scanning, and transmission electron microscopy. Separation ability of the NKU-1-poly (BMA-co-EDMA) monoliths was demonstrated by separating four groups of analytes in CEC, including alkylbenzenes, polycyclic aromatic hydrocarbon, aniline series and naphthyl substitutes. Compared with bare monolithic (column efficiency of 100,000plates/m), the NKU-1-poly (BMA-co-EDMA) monoliths have displayed greater column efficiency (maximum 210,000plates/m) and higher permeability, as well as less peak tailing. The results showed that the NKU-1-poly (BMA-co-EDMA) monoliths are promising stationary phases for CEC separations. PMID:27432788

  19. Polymethacrylate monolithic columns for hydrophilic interaction liquid chromatography prepared using a secondary surface polymerization.

    PubMed

    Currivan, Sinéad; Macak, Jan M; Jandera, Pavel

    2015-07-10

    Zwitterionic methacrylate based polymeric monolithic columns were prepared in two-step polymerizations, with reduced polymerization times. Characteristic properties such as hydrodynamic permeability, porosity, retention factors, and pore size distribution charts were used for column evaluation. A scaffold column was fabricated by polymerization of poly(lauryl methacrylate-co-tetraethyleneglycol dimethacrylate) and was used without further modification as a support for a poly(N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl)ammonium betaine-co-bisphenol A glycerolate dimethacrylate) second monolith layer with zwitterionic functionality, for HILIC separations. An additional internal structure was formed by the second monolithic layer. The fabrication procedure was reproducible with RSD<5%. Field emission scanning electron microscopy has also been used to investigate column pore morphology, using a novel technique where the polymeric material is imaged directly, without coverage with a conducting film or particles. The new polar monolithic columns were used for HILIC separations of phenolic acids, flavones, nucleosides, and bases of nucleic acids, with similar efficiencies but different selectivities for zwitterionic methacrylate monolithic columns recently prepared by single step polymerization.

  20. Polymethacrylate monolithic columns for hydrophilic interaction liquid chromatography prepared using a secondary surface polymerization.

    PubMed

    Currivan, Sinéad; Macak, Jan M; Jandera, Pavel

    2015-07-10

    Zwitterionic methacrylate based polymeric monolithic columns were prepared in two-step polymerizations, with reduced polymerization times. Characteristic properties such as hydrodynamic permeability, porosity, retention factors, and pore size distribution charts were used for column evaluation. A scaffold column was fabricated by polymerization of poly(lauryl methacrylate-co-tetraethyleneglycol dimethacrylate) and was used without further modification as a support for a poly(N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl)ammonium betaine-co-bisphenol A glycerolate dimethacrylate) second monolith layer with zwitterionic functionality, for HILIC separations. An additional internal structure was formed by the second monolithic layer. The fabrication procedure was reproducible with RSD<5%. Field emission scanning electron microscopy has also been used to investigate column pore morphology, using a novel technique where the polymeric material is imaged directly, without coverage with a conducting film or particles. The new polar monolithic columns were used for HILIC separations of phenolic acids, flavones, nucleosides, and bases of nucleic acids, with similar efficiencies but different selectivities for zwitterionic methacrylate monolithic columns recently prepared by single step polymerization. PMID:26022313

  1. Computational fluid dynamics simulations yielding guidelines for the ideal internal structure of monolithic liquid chromatography columns.

    PubMed

    Gzil, P; Baron, G V; Desmet, G

    2003-04-01

    A theoretical calculation of the separation performance of a (hypothetical) micro-structured monolithic LC column is presented, confirming that the polydispersity effect in parallel bundle columns can theoretically be eliminated to a very large extent by radially redistributing the mobile phase fluid at regular intervals. It is demonstrated that the flow can be redistributed in such a way that the advantage coming from the suppression of the polydispersity effect largely exceeds the losses caused by the additional pressure-drop and band broadening. The presently considered micro-structured column would allow to perform N > 100,000 plate separations in a few hundred of seconds, i.e., about an order of magnitude faster than the best possible packed bed and monolithic HPLC columns, while offering the same mass loadability. This clearly demonstrates that the currently available LC columns are still far away from the absolute resolution limit of the ideal, fully optimised LC column.

  2. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes.

    PubMed

    Jonnada, Murthy; El Rassi, Ziad

    2015-08-28

    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of <1% and ∼2-3.5%, respectively, were obtained. Six standard proteins were readily separated on the NMM column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient.

  3. [Preparation and evaluation of pepsin affinity organic polymer capillary monolithic column].

    PubMed

    Chi, Cuijie; Wang, Wei; Ji, Yibing

    2014-08-01

    The protein modified monolithic column in affinity capillary electrochromatography (CEC) has attracted considerable attention over the past decades because of its great enantioseparation ability. A porous polymethacrylate ester-based capillary monolithic column poly (glycidyl methacrylate-co-ethyleneglycol dimethacrylate) (poly (GMA-co-EDMA)) was prepared by in situ co-polymerization. The process was initiated thermally by azobisisobutyronitrile (AIBN). The polymerization mixture contained GMA as the function monomer and EDMA as the crosslinking agent with 1,4-butanediol and 1-propanol as the binary porogen solvent. Under the optimized reaction conditions, including the proportion of monomer and porogens, reaction temperature etc, the column exhibited a uniform structure, sufficient permeability and excel- lent pressure resistance. The separation of alkyl benzenes on the column was mainly based on typical reversed-phase chromatographic retention mechanism. The reproducibility and stability were good with RSDs less than 9. 0%. A pepsin functionalized organic polymer monolith was prepared by covalently bonded pepsin to poly(GMA-co-EDMA) monolith with glutaraldehyde as a spacer based on the activity of epoxide group. The enantioseparation performance of the pepsin affinity monolith for basic enantiomers has been investigated by CEC. Nefopam, amlodipine, citalopram and chlorpheniramine were resolved, and baseline separations of nefopam, amlodipine, citalopram were achieved. The influences of pH, operating voltage, temperature and sample quantity used on the chiral separation were studied. The chiral recognition mechanism of enantiomers on the monolithic column in CEC is discussed. This work developed a new method for the prepataion and application of protein affinity monolith in CEC.

  4. Recent advances in the preparation and application of monolithic capillary columns in separation science.

    PubMed

    Hong, Tingting; Yang, Xi; Xu, Yujing; Ji, Yibing

    2016-08-10

    Novel column technologies involving various materials and efficient reactions have been investigated for the fabrication of monolithic capillary columns in the field of analytical chemistry. In addition to the development of these miniaturized systems, a variety of microscale separation applications have achieved noteworthy results, providing a stepping stone for new types of chromatographic columns with improved efficiency and selectivity. Three novel strategies for the preparation of capillary monoliths, including ionic liquid-based approaches, nanoparticle-based approaches and "click chemistry", are highlighted in this review. Furthermore, we present the employment of state-of-the-art capillary monolithic stationary phases for enantioseparation, solid-phase microextraction, mixed-mode separation and immobilized enzyme reactors. The review concludes with recommendations for future studies and improvements in this field of research. PMID:27282747

  5. Recent advances in the preparation and application of monolithic capillary columns in separation science.

    PubMed

    Hong, Tingting; Yang, Xi; Xu, Yujing; Ji, Yibing

    2016-08-10

    Novel column technologies involving various materials and efficient reactions have been investigated for the fabrication of monolithic capillary columns in the field of analytical chemistry. In addition to the development of these miniaturized systems, a variety of microscale separation applications have achieved noteworthy results, providing a stepping stone for new types of chromatographic columns with improved efficiency and selectivity. Three novel strategies for the preparation of capillary monoliths, including ionic liquid-based approaches, nanoparticle-based approaches and "click chemistry", are highlighted in this review. Furthermore, we present the employment of state-of-the-art capillary monolithic stationary phases for enantioseparation, solid-phase microextraction, mixed-mode separation and immobilized enzyme reactors. The review concludes with recommendations for future studies and improvements in this field of research.

  6. Separation of hydrophobic metabolites using monolithic silica column in high-performance liquid chromatography and supercritical fluid chromatography.

    PubMed

    Bamba, Takeshi; Fukusaki, Eiichiro

    2009-08-01

    Monolithic silica columns have very low back-pressures and offer several advantages over conventional columns packed with spherical particles, such as high separation efficiency and rapid analysis. In this review, we report the applicability of monolithic silica columns for the analysis of complex hydrophobic metabolites. We have used monolithic columns in HPLC and developed a separation technique for the high-speed and high-resolution analysis of the geometric analogs of natural polyprenols. We also used monolithic columns in supercritical fluid chromatography for the successful separation of the structural isomers of carotenoids after deciding the analytical conditions that were suitable for this separation and have developed a method for profiling biological samples containing complex matrices. We have proved that excellent resolution can be obtained by connecting a number of monolithic columns in series.

  7. Monolithic capillary columns based on pentaerythritol tetraacrylate for peptide analysis

    NASA Astrophysics Data System (ADS)

    Kucherenko, E. V.; Melnik, D. M.; Korolev, A. A.; Kanateva, A. Yu.; Pirogov, A. V.; Kurganov, A. A.

    2015-09-01

    Monolythic medium-polar capillary columns based on pentaerythritol tetraacrylate were optimized for separation of peptides. The synthesis temperature and time, the fraction of monomer in the initial polymerization mixture, and the nature of alcohol contained in the complex porogen were chosen as optimization parameters. The highest efficiency was attained for columns obtained with 33 and 34% monomer at a polymerization time of 75 min and a temperature of 75°C. The columns with the optimum structure were effective in separation of a model mixture of five peptides. The sensitivity of the method was 200 ng of peptide per column.

  8. Macroporous polyacrylamide-based monolithic column with immobilized pH gradient for protein analysis.

    PubMed

    Zhu, Guijie; Yuan, Huiming; Zhao, Peng; Zhang, Lihua; Liang, Zhen; Zhang, Weibing; Zhang, Yukui

    2006-09-01

    Monolithic materials were prepared in capillaries by in situ polymerization of acrylamide, glycidyl methacrylate, and N,N'-methylenebisacrylamide in the presence of 1,4-butanediol, dodecanol, and DMSO as porogens. With Ampholine attached to the surface of the porous monolith via epoxide groups, a monolithic-IPG (M-IPG) was formed and showed good mechanical and chemical stability. With such a column immobilized by Ampholine 3.5-10, IEF-MIX 3.6-9.3 was separated and good linearity was obtained. The CIEF behavior of M-IPG was evinced by comparing the current with that in the open tubular capillary. In addition, the protein mixtures excreted from lung cancer cells of rats were analyzed with such a new M-IPG column.

  9. Macroporous polyacrylamide-based monolithic column with immobilized pH gradient for protein analysis.

    PubMed

    Zhu, Guijie; Yuan, Huiming; Zhao, Peng; Zhang, Lihua; Liang, Zhen; Zhang, Weibing; Zhang, Yukui

    2006-09-01

    Monolithic materials were prepared in capillaries by in situ polymerization of acrylamide, glycidyl methacrylate, and N,N'-methylenebisacrylamide in the presence of 1,4-butanediol, dodecanol, and DMSO as porogens. With Ampholine attached to the surface of the porous monolith via epoxide groups, a monolithic-IPG (M-IPG) was formed and showed good mechanical and chemical stability. With such a column immobilized by Ampholine 3.5-10, IEF-MIX 3.6-9.3 was separated and good linearity was obtained. The CIEF behavior of M-IPG was evinced by comparing the current with that in the open tubular capillary. In addition, the protein mixtures excreted from lung cancer cells of rats were analyzed with such a new M-IPG column. PMID:16915568

  10. Analyses of preservatives by capillary electrochromatography using methacrylate ester-based monolithic columns.

    PubMed

    Huang, Hsi-Ya; Chiu, Chen-Wen; Huang, I-Yun; Yeh, Jui-Ming

    2004-10-01

    Five common food preservatives were analyzed by capillary electrochromatography, utilizing a methacrylate ester-based monolithic capillary as separation column. In order to optimize the separation of these preservatives, the effects of the pore size of the polymeric stationary phase, the pH and composition of the mobile phase on separation were examined. For all analytes, it was found that an increase in pore size caused a reduction in retention time. However, separation performances were greatly improved in monolithic columns with smaller pore sizes. The pH of the mobile phase had little influence on separation resolution, but a dramatic effect on the amount of sample that was needed to be electrokinetically injected into the monolithic column. In addition, the retention behaviors of these analytes were strongly influenced by the level of acetonitrile in the mobile phase. An optimal separation of the five preservatives was obtained within 7.0 min with a pH 3.0 mobile phase composed of phosphate buffer and acetonitrile 35:65 v/v. Finally, preservatives in real commercial products, including cold syrup, lotion, wine, and soy sauces, were successfully determined by the methacrylate ester-based polymeric monolithic column under this optimized condition.

  11. Ionic liquid-based zwitterionic organic polymer monolithic column for capillary hydrophilic interaction chromatography.

    PubMed

    Wang, Tingting; Chen, Yihui; Ma, Junfeng; Zhang, Xiaodan; Zhang, Lihua; Zhang, Yukui

    2015-08-21

    In the current study, a novel ionic liquid-based zwitterionic organic polymer monolithic column was developed by copolymerizing 1-vinyl-3-(butyl-4-sulfonate) imidazolium, acrylamide and N,N'-methylenebisacrylamide in a quaternary porogenic solvent consisting of formamide, dimethyl sulphoxide, polyethylene glycol 8000 and polyethylene glycol 10,000 for capillary hydrophilic interaction chromatography. The monolithic stationary phase was optimized by adjusting the amount of monomer in the polymerization solution along with the composition of porogenic solvent. The optimized monolith exhibited excellent selectivity and favorable retention for nucleosides and benzoic acid derivatives. The primary factors affecting the separation efficiency of the monolithic column (including acetonitrile content, pH, and buffer salt concentration in the mobile phase) have been thoroughly evaluated. Excellent reproducibility of the retention times for five nucleosides was achieved, with relative standard deviations of run-to-run (n = 3), column-to-column (n = 3) and batch-to-batch (n = 3) in the range of 0.18-0.48%, 2.33-4.20% and 3.07-6.50%, respectively.

  12. New zwitterionic polymethacrylate monolithic columns for one- and two-dimensional microliquid chromatography.

    PubMed

    Jandera, Pavel; Staňková, Magda; Hájek, Tomáš

    2013-08-01

    We prepared 0.53 and 0.32 mm id monolithic microcolumns by in situ copolymerization of a zwitterionic sulfobetaine functional monomer with bisphenol A glycerolate dimethacrylate (BIGDMA) and dioxyethylene dimetacrylate crosslinkers. The columns show a dual retention mechanism (hydrophilic-interaction mode) in acetonitrile-rich mobile phases and RP in highly aqueous mobile phases. The new 0.53 mm id columns provided excellent reproducibility, retention, and separation selectivity for phenolic acids and flavonoids. The new zwitterionic monolithic columns are highly orthogonal, with respect to alkyl silica stationary phases, not only in the hydrophilic-interaction mode but also in the RP mode. The optimized monolithic zwitterionic microcolumn of 0.53 mm id was employed in the first dimension, either in the aqueous normal-phase or in the RP mode, coupled with a short nonpolar core-shell column in the second dimension, for comprehensive 2D LC separations of phenolic and flavonoid compounds. When the 2D setup with the sulfobetaine-BIGDMA column was used for repeated sample analysis, with alternating gradients of decreasing (hydrophilic-interaction mode), and increasing (RP mode) concentration of acetonitrile on the sulfobetaine-BIGDMA column in the first dimension, useful complementary information on the sample could be obtained. PMID:23729220

  13. Hydrothermal preparation of hybrid carbon/silica monolithic capillary column for liquid chromatography.

    PubMed

    Yang, Peiling; Wang, Wentao; Xiao, Xing; Jia, Li

    2014-08-01

    A simple, easy and economical approach for the preparation of a hybrid carbon/silica monolithic capillary column was described for the first time by using silica monolith as framework in combination with hydrothermal carbonization at 180°C. During the preparation process, formamide was introduced to the reaction solutions to reduce the dissolution rate of monolithic silica skeleton and its optimal concentration was 1.5 M. Fourier transform infrared spectrometry, scanning electron microscopy, energy dispersive X-ray spectrometry, and inverse size exclusion chromatography were carried out to characterize the as-prepared column. The results demonstrated that carbon spheres ranging from 150 to 1000 nm were successfully attached to the surface of silica skeleton. The prepared hybrid carbon/silica column had a permeability of 4.4 × 10(-14) m(2). Chromatographic performance of the column was evaluated by separation of various compounds including alkylbenzenes, nucleosides and bases, and aromatic acids. The column exhibited an efficiency of 75,000 plates/m for butylbenzene at the optimal linear velocity of 0.23 mm/s. The successful separation of these compounds and the study on mechanism indicated that the column can be applied in mixed-mode chromatography. PMID:24830747

  14. CEC column behaviour of butyl and lauryl methacrylate monoliths prepared in non-aqueous media.

    PubMed

    Cantó-Mirapeix, Amparo; Herrero-Martínez, José M; Mongay-Fernández, Carlos; Simó-Alfonso, Ernesto F

    2009-02-01

    Polymeric monolithic stationary phases for capillary electrochromatography were prepared using two bulk monomers, butyl methacrylate (BMA) and lauryl methacrylate (LMA), by in situ polymerization in non-aqueous media. The effect of 1,4-butanediol/1-propanol ratio on porous properties was investigated separately for each monomer, keeping the proportion of monomers to pore-forming solvents fixed at 40:60 wt:wt. Also, mixtures of BMA and LMA at different 1,4-butanediol/1-propanol ratios were studied for tailoring the morphological features of the monolithic columns. The chromatographic performance of the different columns was evaluated by means of van Deemter plots of polycyclic aromatic hydrocarbons. Mercury-intrusion porosimetry, SEM, and nitrogen-adsorption measurements were also performed in order to understand their retention behaviour and porous properties. A comparison of these features was also performed for monoliths made with one bulk monomer (BMA or LMA) and with mixtures of both. These mixed monoliths showed satisfactory efficiencies and analysis times compared with those made with one bulk monomer; thus, the BMA-LMA monoliths constitute an attractive alternative to manipulate the electrochromatographic properties of methacrylate beds in CEC. PMID:19170053

  15. One-pot preparation of a sulfamethoxazole functionalized affinity monolithic column for selective isolation and purification of trypsin.

    PubMed

    Xiao, Yuan; Guo, Jialiang; Ran, Danni; Duan, Qianqian; Crommen, Jacques; Jiang, Zhengjin

    2015-06-26

    A facile and efficient "one-pot" copolymerization strategy was used for the preparation of sulfonamide drug (SA) functionalized monolithic columns. Two novel SA-immobilized methacrylate monolithic columns, i.e. poly(GMA-SMX-co-EDMA) and poly(GMA-SAA-co-EDMA) were prepared by one-pot in situ copolymerization of the drug ligand (sulfamethoxazole (SMX) or sulfanilamide (SAA)), the monomer (glycidyl methacrylate, GMA) and the cross-linker (ethylene dimethacrylate, EDMA) within 100 μm i.d. capillaries under optimized polymerization conditions. The physicochemical properties and column performance of the fabricated monolithic columns were characterized by elemental analysis, scanning electron microscopy and micro-HPLC. Satisfactory column permeability, efficiency and separation performance were obtained on the optimized poly(GMA-SMX-co-EDMA) monolithic column for small molecules, such as a standard test mixture and eight aromatic ketones. Notably, it was found that the poly(GMA-SMX-co-EDMA) monolith showed a selective affinity to trypsin, while the poly(GMA-SAA-co-EDMA) monolith containing sulfanilamide did not exhibit such affinity at all. This research not only provides a novel monolith for the selective isolation and purification of trypsin, but it also offers the possibility to easily prepare novel drug functionalized methacrylate monoliths through a one-pot copolymerization strategy.

  16. Amine Gradient Stationary Phases on In-House Built Monolithic Columns for Liquid Chromatography.

    PubMed

    Dewoolkar, Veeren C; Jeong, Lena N; Cook, Daniel W; Ashraf, Kayesh M; Rutan, Sarah C; Collinson, Maryanne M

    2016-06-01

    Stationary phase gradients on monolithic silica columns have been successfully and reproducibly prepared and characterized with comparisons made to uniformly modified stationary phases. Stationary phase gradients hold great potential for use in liquid chromatography (LC), both in terms of simplifying analysis as well as providing novel selectivity. In this work, we demonstrate the creation of a continuous stationary phase gradient on in-house synthesized monolithic columns by infusing an aminoalkoxysilane solution through the silica monoliths via controlled rate infusion. The presence of amine and its distribution along the length of gradient and uniformly modified columns were assessed via X-ray photoelectron spectroscopy (XPS). XPS showed a clear gradient in surface coverage along the length of the column for the gradient stationary phases while a near uniform distribution on the uniformly modified stationary phases. To demonstrate the application of these gradient stationary phases, the separations of both nucleobases and weak acids/weak bases on these gradient stationary phases have been compared to uniformly modified and unmodified silica columns. Of particular note, the retention characteristics of 11 gradient columns, 5 uniformly modified columns, and 5 unmodified columns have been tested to establish the reproducibility of the synthetic procedures. Standard deviations of the retention factors were in the range from 0.06 to 0.5, depending on the analyte species. We show that selectivity is achieved with the stationary phase gradients that are significantly different from either uniformly modified amine or unmodified columns. These results indicate the significant promise of this strategy for creating novel stationary phases for LC. PMID:27203513

  17. Hexavalent chromium removal performance of anionic functionalized monolithic polymers: column adsorption, regeneration and modelling.

    PubMed

    Barlik, Necla; Keskinler, Bülent; Kocakerim, M Muhtar

    2016-01-01

    Anionic functionalized monolithic macro-porous polymers were used for the removal of hexavalent chromium(VI) anions from aqueous solution in column experiments. At a flux of 1.0 cm min and 30 mg Cr(VI) L(-1) feed concentration, breakthrough capacity and apparent capacity were 0.066 g Cr(VI) g(-1) anionic monolith and 0.144 g Cr(VI) g(-1) anionic monolith, respectively. The degree of column utilization was found to lie in the range 41-46%. Two kinetic models, theoretical and Thomas models, were applied to experimental data to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design. The simulation of the whole breakthrough curve was effective with the models. At a flux of 1.0 cm min and 30 mg Cr(VI) L(-1) feed concentration, the dispersion coefficient and adsorption equilibrium constant (K) were 3.14 × 10(-7) m s(-1) and 3,840, respectively. Also, Thomas model parameters k1 (rate constant of adsorption) and qm (equilibrium solid-phase concentration of sorbed solute) were 1.08 × 10(-3) L mg(-1) min(-1) and 0.124 g g(-1), respectively. After reaching equilibrium adsorption capacity, the monoliths were regenerated using 1 N HCl and were subsequently re-tested. It was found that the regeneration efficiency reduced from 98% after second usage to 97% after the third usage. PMID:27003067

  18. On-column enrichment and surface-enhanced Raman scattering detection in nanoparticles functionalized porous capillary monolith.

    PubMed

    Jiang, Qian; Zeng, Tian; Yang, Song; Chen, Qian; Chen, Lei; Ye, Yong; Zhou, Ji; Xu, Shuping

    2015-04-15

    A monolithic column functionalized with gold nanoparticles (GNPs) was designed to provide ultrasensitive detection with surface-enhanced Raman scattering (SERS). The monolithic column based on poly (glycidyl methacrylate-co-ethylene dimethacrylate) (GMA-co-EDMA) was served as the enrichment sorbent to concentrate GNPs and targets. We found that 60 nm GNPs-functionalized monolithic columns demonstrated the best SERS enhancement, and the lowest detectable concentration for PATP and CV could be achieved at 10(-7) and 10(-11) M, respectively. Moreover, the columns exhibit a good reproducibility in both spot-to-spot (∼10%) and batch-to-batch (∼15%). The SERS monolithic column with a high sensitivity and reproducibility has a great potential in the field-based rapid detection of targets in complex real-world samples. PMID:25681809

  19. Silica-based monolithic capillary columns modified by liposomes for characterization of analyte-liposome interactions by capillary liquid chromatography.

    PubMed

    Moravcová, Dana; Planeta, Josef; Wiedmer, Susanne K

    2013-11-22

    This study introduces a silica-based monolith in a capillary format (0.1 mm × 100 mm) as a support for immobilization of liposomes and its characterization in immobilized liposome chromatography. Silica-based monolithic capillary columns prepared by acidic hydrolysis of tetramethoxysilane in the presence of polyethylene glycol and urea were modified by (3-aminopropyl)trimethoxysilane, whereby amino groups were introduced to the monolithic surface. These groups undergo reaction with glutaraldehyde to form an iminoaldehyde, allowing covalent binding of pre-formed liposomes containing primary amino groups. Two types of phospholipid vesicles were used for column modification; these were 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphatidyl choline with and without 1,2-diacyl-sn-glycero-3-phospho-L-serine. The prepared columns were evaluated under isocratic separation conditions employing 20mM phosphate buffer at pH 7.4 as a mobile phase and a set of unrelated drugs as model analytes. The liposome layer on the synthesized columns significantly changed the column selectivity compared to the aminopropylsilylated monolithic stationary phase. Monolithic columns modified by liposomes were stable under the separation conditions, which proved the applicability of the suggested preparation procedure for the synthesis of capillary columns dedicated to study analyte-liposome interactions. The column efficiency originating from the silica monolith was preserved and reached, e.g., more than 120,000 theoretical plates/m for caffeine as a solute. PMID:23978749

  20. Detailed characterization of the kinetic performance of first and second generation silica monolithic columns for reversed-phase chromatography separations.

    PubMed

    Cabooter, Deirdre; Broeckhoven, Ken; Sterken, Roman; Vanmessen, Alison; Vandendael, Isabelle; Nakanishi, Kazuki; Deridder, Sander; Desmet, Gert

    2014-01-17

    The kinetic performance of commercially available first generation and prototype second generation silica monoliths has been investigated for 2.0mm and 3.0-3.2mm inner diameter columns. It is demonstrated that the altered sol-gel process employed for the production of second generation monoliths results in structures with a smaller characteristic size leading to an improved peak shape and higher efficiencies. The permeability of the columns however, decreases significantly due to the smaller throughpore and skeleton sizes. Scanning electron microscopy pictures suggest the first generation monoliths have cylindrical skeleton branches, whereas the second generation monoliths rather have skeleton branches that resemble a single chain of spherical globules. Using recently established correlations for the flow resistance of cylindrical and globule chain type monolithic structures, it is demonstrated that the higher flow resistance of the second generation monoliths can be entirely attributed to their smaller skeleton sizes, which is also evident from the external porosity that is largely the same for both monolith generations (ɛe∼0.65). The recorded van Deemter plots show a clear improvement in efficiency for the second generation monoliths (minimal plate heights of 13.6-14.1μm for the first and 6.5-8.2μm for the second generation, when assessing the plate count using the Foley-Dorsey method). The corresponding kinetic plots, however, indicate that the much reduced permeability of the second generation monoliths results in kinetic performances (time needed to achieve a given efficiency) which are only better than those of the first generation for plate counts up to N∼45,000. For more complex samples (N≥50,000), the first generation monoliths can intrinsically still provide faster analysis due to their high permeability. It is also demonstrated that - despite the improved efficiency of the second generation monoliths in the practical range of separations (N=10

  1. Tailoring the macroporous structure of monolithic silica-based capillary columns with potential for liquid chromatography.

    PubMed

    Laschober, Stefan; Sulyok, Michael; Rosenberg, Erwin

    2007-03-01

    The present work aims at the optimisation of the synthesis of methyl-silsesquioxane monolithic capillary columns using a sol-gel based protocol. The influence of reaction conditions such as temperature, reaction mixture composition and catalyst concentration has been examined. The morphology of the products was studied by scanning electron microscopy and nitrogen adsorption. Monolithic capillary columns were obtained with a skeleton-like structure with open pores. Pore diameters vary from 0.8 to 15 microm, diameters of the xerogel network vary from 0.4 to 12 microm, respectively. Specific surface areas up to 334 m2/g have been observed, however, many materials did not possess areas above few m2/g which represents the limit of detection of the nitrogen porosimetry measurements. Excellent adhesion to the capillary wall was observed in all cases, and drying was possible at ambient conditions without the formation of cracks. PMID:17241639

  2. Isolation and purification of blood group antigens using immuno-affinity chromatography on short monolithic columns.

    PubMed

    Mönster, Andrea; Hiller, Oliver; Grüger, Daniela; Blasczyk, Rainer; Kasper, Cornelia

    2011-02-01

    Monolithic columns have gained increasing attention as stationary phases for the separation of biomolecules and biopharmaceuticals. In the present work the performance of monolithic convective interaction media (CIM(®)) chromatography for the purification of blood group antigens was established. The proteins employed in this study are derived from blood group antigens Knops, JMH and Scianna, equipped both with a His-tag and with a V5-tag by which they can be purified. In a first step a monoclonal antibody directed against the V5-tag was immobilized on a CIM(®) Disk with epoxy chemistry. After this, the immobilized CIM(®) Disk was used in immuno-affinity chromatography to purify the three blood group antigens from cell culture supernatant. Up-scaling of the applied technology was carried out using CIM(®) Tubes. In comparison to conventional affinity chromatography, blood group antigens were also purified via His-tag using a HiTrap(®) metal-affinity column. The two purifications have been compared regarding purity, yield and purification speed. Using the monolithic support, it was possible to isolate the blood group antigens with a higher flow rate than using the conventional bed-packed column.

  3. Effect of polyethylene glycol on pore structure and separation efficiency of silica-based monolithic capillary columns.

    PubMed

    Hara, Takeshi; Desmet, Gert; Baron, Gino V; Minakuchi, Hiroyoshi; Eeltink, Sebastiaan

    2016-04-15

    Monolithic silica materials (first unclad monolith rods, then monolithic capillary columns) were prepared using various amounts of polyethylene glycols (PEGs) with different molecular weight (MW). The monolith rods were used to examine the mesoporosity by argon physisorption technique, and the macroporosity by mercury intrusion porosimetry. Subsequently, silica-based monolithic capillary columns with an inner diameter of 100 μm were produced using the same preparation conditions as used for the rods. The results obtained with the monolith rods showed the following important findings: (1) it is feasible to fabricate monolithic silica rods possessing macropore size of 0.5-1.4 μm by tuning the amount of PEGs (independently of the MW), whereas the macropore volume and the mesoporosity remain similar. (2) the smallest macropore size (0.5 μm) rod prepared with PEG having a MW=20,000g/mol provided a narrower macropore size distribution than with PEG with MW=10,000g/mol. The monolithic capillary columns produced with the different PEG type showed similar retention factors for hexylbenzene (k=2.3-2.4) and similar t0-based column permeability (Kv0=2.3-2.4×10(-14)m(2)) in 20:80% (v/v) water:methanol, as expected from the results obtained with the monolith rods. The column prepared with PEG of MW=20,000g/mol gave a plate height of H=4.0 μm for hexylbenzene at an optimal linear velocity of u0=2.6mm/s in 20:80% (v/v) water containing 0.1% formic acid:acetonitrile. To the best of our knowledge, this is the lowest plate height ever recorded for a monolithic column. Comparing the kinetic performance at 30MPa shows that the best monolithic silica column obtained in the present study performs better than the second-generation monolithic silica columns developed up till now in the practically most relevant range of plate numbers (N≤40,000). In this range, the performance is now similar to that of 2.7 μm core-shell particle columns. PMID:26976349

  4. Graphene oxide decorated monolithic column as stationary phase for capillary electrochromatography.

    PubMed

    Zhao, Hongyan; Wang, Yuanchao; Cheng, Heyong; Shen, Yili

    2016-06-24

    In this work, GO bonded monolith (pAS-GO@PS-DVB) as the stationary phase for capillary electrochromatography was fabricated, which was achieved by a simple one-step in-situ copolymerization of styrene and vinylized GO in the presence of divinylbenzene as a cross-linker. GO functionalization was primarily completed using p-aminostyrene based on condensation reaction between amino and carboxyl groups. The characterization by infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy proved the covalent bonding of GO on the monolith. The average pore diameter via Barrett-Joyner-Halenda, specific surface area and pore volume via Brunauer-Emmett-Teller equation by nitrogen adsorption/desorption were determined to be 112.4nm, 485.8m(2)g(-1) and 1.4cm(3)g(-1), respectively. The pAS-GO@PS-DVB monolithic column gave effective separation for a wide range of aromatic compounds, which was based on hydrogen bonding and π-π interactions of GO with polar and/or non-polar organic compounds. The reproducibility in terms of the precisions of migration time, peak height and peak area was estimated below 6% using thiourea and other aromatic compounds. Furthermore, the differences of migration time, peak height and peak area between the first-week analysis and the forth-week analysis were less than 19%, indicating good stability of the proposed monolithic column in one month. The applicability of the pAS-GO@PS-DVB monolith was also demonstrated by baseline separation of three phenols and three anilines. PMID:27211861

  5. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part II. Polymethacrylate-based monolithic column with "covalently" incorporated modified octadecyl fumed silica nanoparticles for reversed-phase chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    This study is concerned with the incorporation of surface modified fumed silica nanoparticles (FSNPs) into polymethacrylate based monolithic columns for use in reversed phase chromatography (RPC) of small solutes and proteins. First, FSNPs were modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) to yield the "hybrid" methacryloyl fumed silica nanoparticle (MFSNP) monomer. The resulting MFSNP was then mixed with glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent composed of cyclohexanol and dodecanol, and the in situ copolymerization of MFSNP, GMM and EDMA was performed in a stainless steel column of 4.6 mm i.d. The silanol groups of the hybrid monolith thus obtained were grafted with octadecyl ligands by perfusing the hybrid monolithic column with a solution of 4% w/v of dimethyloctadecylchlorosilane (DODCS) in toluene while the column was maintained at 110°C for 6h (in a heated HPLC oven). One of the originalities of this study was to demonstrate MFSNP as a novel derivatized "hybrid monomer" in making RPC monolithic columns with surface bound octadecyl ligands. In this respect, the RPC behavior of the monolithic column with "covalently" incorporated FNSPs having surface grafted octadecyl ligands was evaluated with alkylbenzenes, aniline derivatives and phenolic compounds. The results showed that the hybrid poly(GMA-EDMA-MFSNP) having surface bound octadecyl ligands exhibited hydrophobic interactions under reversed phase elution conditions. Furthermore, six standard proteins were baseline separated on the column using a 10min linear gradient elution at increasing ACN concentration in the mobile phase at a flow rate of 1.0mL/min using a 10 cm×4.6mm i.d. column. The relative standard deviations (RSDs) for the retention times of the tested solutes were lower than 2.1% and 2.4% under isocratic elution and gradient elution conditions, respectively. PMID:27059396

  6. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part II. Polymethacrylate-based monolithic column with "covalently" incorporated modified octadecyl fumed silica nanoparticles for reversed-phase chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    This study is concerned with the incorporation of surface modified fumed silica nanoparticles (FSNPs) into polymethacrylate based monolithic columns for use in reversed phase chromatography (RPC) of small solutes and proteins. First, FSNPs were modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) to yield the "hybrid" methacryloyl fumed silica nanoparticle (MFSNP) monomer. The resulting MFSNP was then mixed with glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent composed of cyclohexanol and dodecanol, and the in situ copolymerization of MFSNP, GMM and EDMA was performed in a stainless steel column of 4.6 mm i.d. The silanol groups of the hybrid monolith thus obtained were grafted with octadecyl ligands by perfusing the hybrid monolithic column with a solution of 4% w/v of dimethyloctadecylchlorosilane (DODCS) in toluene while the column was maintained at 110°C for 6h (in a heated HPLC oven). One of the originalities of this study was to demonstrate MFSNP as a novel derivatized "hybrid monomer" in making RPC monolithic columns with surface bound octadecyl ligands. In this respect, the RPC behavior of the monolithic column with "covalently" incorporated FNSPs having surface grafted octadecyl ligands was evaluated with alkylbenzenes, aniline derivatives and phenolic compounds. The results showed that the hybrid poly(GMA-EDMA-MFSNP) having surface bound octadecyl ligands exhibited hydrophobic interactions under reversed phase elution conditions. Furthermore, six standard proteins were baseline separated on the column using a 10min linear gradient elution at increasing ACN concentration in the mobile phase at a flow rate of 1.0mL/min using a 10 cm×4.6mm i.d. column. The relative standard deviations (RSDs) for the retention times of the tested solutes were lower than 2.1% and 2.4% under isocratic elution and gradient elution conditions, respectively.

  7. Rapid determination of sterols in vegetable oils by CEC using methacrylate ester-based monolithic columns.

    PubMed

    Lerma-García, María Jesús; Simó-Alfonso, Ernesto F; Ramis-Ramos, Guillermo; Herrero-Martínez, José M

    2008-11-01

    A method for the determination of sterols in vegetable oils by CEC with UV-Vis detection, using methacrylate ester-based monolithic columns, has been developed. To prepare the columns, polymerization mixtures containing monomers of different hydrophobicities were tried. The influence of composition of polymerization mixture was optimized in terms of porogenic solvent, monomers/porogens and monomer/crosslinker ratios. The composition of the mobile phase was also studied. The optimum monolith was obtained with lauryl methacrylate monomer at 60:40% (wt:wt) lauryl methacrylate/ethylene dimethacrylate ratio and 60 wt% porogens with 20 wt% of 1,4-butanediol (12 wt% 1,4-butanediol in the polymerization mixture). Excellent resolution between sterols was achieved in less than 7 min with an 85:10:5 v/v/v ACN-2-propanol-water buffer containing 5 mM Tris at pH 8.0. The limits of detection were lower than 0.04 mM, and inter-day and column-to-column reproducibilities at 0.75 mM were better than 6.2%. The method was applied to the determination of sterols in vegetable oils with different botanical origins and to detect olive oil adulteration with sunflower and soybean oils.

  8. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part I. Polymethacrylate-based monolithic column with incorporated bare fumed silica nanoparticles for hydrophilic interaction liquid chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    Fumed silica nanoparticles (FSNPs), were incorporated for the first time into a polymethacrylate monolithic column containing glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in order to develop a new monolithic column for hydrophilic interaction high performance liquid chromatography (HILIC). When compared to poly(GMM-EDMA) monolithic column without FSNPs, the same monolithic column with incorporated FSNPs yielded important effects on HILIC separations. The effects of monomers and FSNPs content of the polymerization mixture on the performance of the monolithic column were examined in details, and the optimized stationary phase was investigated over a wide range of mobile phase composition with polar acidic, weakly basic and neutral analytes including hydroxy benzoic acids, nucleotides, nucleosides, dimethylformamide, formamide and thiourea. The retention of these analytes was mainly controlled by hydrophilic interactions with the FSNPs and electrostatic repulsion from the negatively charged silica surface in the case of hydroxy benzoic acids and nucleotides. The electrostatic repulsion was minimized by decreasing the pH of the aqueous component of the mobile phase, which in turn enhanced the retention of acidic solutes. Nucleotides were best separated using step gradient elution at decreasing pH as well as ACN concentration in the mobile phase. Improved peak shape and faster analysis of nucleosides were attained by a fast linear gradient elution with a shallow decrease in the ACN content of the ACN-rich mobile phase. The run-to-run and column-to-column reproducibility were satisfactory. The percent relative standard deviations (%RSDs) for the retention times of tested solutes were lower than 2.5% under isocratic conditions and lower than 3.5 under gradient conditions. PMID:27059399

  9. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part I. Polymethacrylate-based monolithic column with incorporated bare fumed silica nanoparticles for hydrophilic interaction liquid chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    Fumed silica nanoparticles (FSNPs), were incorporated for the first time into a polymethacrylate monolithic column containing glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in order to develop a new monolithic column for hydrophilic interaction high performance liquid chromatography (HILIC). When compared to poly(GMM-EDMA) monolithic column without FSNPs, the same monolithic column with incorporated FSNPs yielded important effects on HILIC separations. The effects of monomers and FSNPs content of the polymerization mixture on the performance of the monolithic column were examined in details, and the optimized stationary phase was investigated over a wide range of mobile phase composition with polar acidic, weakly basic and neutral analytes including hydroxy benzoic acids, nucleotides, nucleosides, dimethylformamide, formamide and thiourea. The retention of these analytes was mainly controlled by hydrophilic interactions with the FSNPs and electrostatic repulsion from the negatively charged silica surface in the case of hydroxy benzoic acids and nucleotides. The electrostatic repulsion was minimized by decreasing the pH of the aqueous component of the mobile phase, which in turn enhanced the retention of acidic solutes. Nucleotides were best separated using step gradient elution at decreasing pH as well as ACN concentration in the mobile phase. Improved peak shape and faster analysis of nucleosides were attained by a fast linear gradient elution with a shallow decrease in the ACN content of the ACN-rich mobile phase. The run-to-run and column-to-column reproducibility were satisfactory. The percent relative standard deviations (%RSDs) for the retention times of tested solutes were lower than 2.5% under isocratic conditions and lower than 3.5 under gradient conditions.

  10. Miniaturized monolithic columns for the electrochromatographic separation and SERS detection of molecules of exobiological interest

    NASA Astrophysics Data System (ADS)

    Carbonnier, Benjamin; Guerrouache, Mohamed

    Development of miniaturized separation and detection media represents one of the major challenges in the field of modern analytical chemistry dedicated to space exploration. To date, gas chromatography-mass spectrometry has been selected as the method of choice for exobiology flight experiments for seeking for organic molecules and especially potential chemical indicators of life. [1] Liquid phase separation methods have also been developed with for instance, the so-called Mars Organic Analyzer (MOA) capillary electrophoresis (CE) microchip.[2] Although CE offers the advantages of easy miniaturization and high separation efficiency it suffers from a lack of selectivity towards a broad range of analytes with varied chemical nature. In this respect, we propose the use of capillary columns filled with monolithic stationary phases for the electrochromatographic separation of organic molecules of exobiology interest. Polymer monoliths have attracted a great deal of interest in analytical science over the last years as (electro)chromatographic stationary phases [3], immunosensors [4]. Beyond the intrinsic properties of monolithic polymers, i.e. fast mass transport between the monolithic support and the surrounding fluid and high permeability, other major advantages are their easy in situ preparation and tuning of surface functionality. Indeed, monoliths can be simply prepared through free radical copolymerization of a homogeneous mixture made of monomers, cross-linkers, porogenic solvents and initiator. UV-initiation process has been exploited to the synthesis of a discrete section of monolith as a flow-through active element within the confines of micro channels [5,6] while two-step strategies have been reported for the design of varied adsorbent starting with a generic monolith [7,8]. Although a nearly limitless range of monolithic supports can be prepared by this traditional method, the resulting monoliths exhibit unique function. In this contribution, we describe an

  11. Fast HPLC for quality control of Harpagophytum procumbens by using a monolithic silica column: method transfer from conventional particle-based silica column.

    PubMed

    Schmidt, Alexander H

    2005-05-01

    The applicability of a monolithic C18-bonded silica column for the rapid HPLC separation of ingredients in medicinal plants and their phytopharmaceutical preparations has been evaluated in the author's laboratory. In this presentation, an existing method for the determination of the iridoid glycoside harpagoside in Harpagophytum procumbens (Devil's Claw) was successfully transferred from a conventional particle-based C18 silica column to a monolithic silica column. The very high porosity of the stationary phase allows chromatography with a much lower backpressure than on conventional columns. Therefore, the flow rate could be easily increased from 0.8 mL/min (particle-based column) to 5 mL/min (monolithic column) and the run-time reduced from 30 to 5 min (that is a reduction about 85% !), without losing any chromatographic resolution of the compound of interest. The amount of harpagoside was measured with the original method on a conventional particle-based silica column and on the adapted method on a monolithic silica column. The statistical mean t-test showed no significant differences of the variances and the means indicating that the fast HPLC method is an acceptable alternative. The shorter analysis time makes the method very valuable for commercial quality control of Harpagophytum extracts and its pharmaceutical preparations. PMID:15909544

  12. Simultaneous Determination of Five Alkaloid Compounds in a Drug Based on a Hydrophilic Monolithic Column by Capillary Electrochromatography.

    PubMed

    Chen, Zongbao; Ye, Qing; Liu, Linghai; Dong, Hongxia

    2016-01-01

    A novel capillary electrochromatography (CEC) method was developed by using a hydrophilic monolithic column for the simultaneous determination of five alkaloids in a drug. The monolithic stationary phase was first prepared via in situ polymerization of acrylamide (AM), glycidyl methacrylate (GMA), N,N'-methylenebisacrylamide (MBA) and 2-acrylamido-2-methyl-1-propane-sulfonic acid (AMPS) in a ternary porogen solvent system consisting of cyclohexanol, dodecanol and toluene. The obtained monolithic stationary phase was subsequently modified by 0.1 mol/L ammonia water for opening epoxide groups of GMA. The separation performance and efficiency of the resulting monolithic column were investigated by the use of five compounds (thiourea, aniline, naphthylamine, diphenylamine and dimethyl acetamide) by CEC. The optimized monolithic column has obtained high column efficiencies with 74,000-121,000 theoretical plates/m. Finally, the prepared monolithic column was used to separate and determine five alkaloids (piperine, nuciferine, kukoline, berberine and tetrandrine) using CEC. Under the conditions of acetonitrile/10 mM phosphate buffer solution (65/35, v/v, pH 8.5) and 15 kV applied voltage, the baseline separation of five alkaloids was achieved. The proposed method has been successfully applied to the determination of berberine in a tablet sample. The percentage of recovery of spiked tablet samples ranged from 93.4 to 108.0% with relative standard deviations (RSDs) <9.20%. PMID:26187925

  13. Kinetic efficiency of polar monolithic capillary columns in high-pressure gas chromatography.

    PubMed

    Kurganov, A A; Korolev, A A; Shiryaeva, V E; Popova, T P; Kanateva, A Yu

    2013-11-01

    Poppe plots were used for analysis of kinetic efficiency of monolithic sorbents synthesized in quartz capillaries for utilization in high-pressure gas chromatography. Values of theoretical plate time and maximum number of theoretical plates occurred to depend significantly on synthetic parameters such as relative amount of monomer in the initial polymerization mixture, temperature and polymerization time. Poppe plots let one to find synthesis conditions suitable either for high-speed separations or for maximal efficiency. It is shown that construction of kinetic Poppe curves using potential Van Deemter data demands compressibility of mobile phase to be taken into consideration in the case of gas chromatography. Model mixture of light hydrocarbons C1 to C4 was then used for investigation of influence of carrier gas nature on kinetic efficiency of polymeric monolithic columns. Minimal values of theoretical plate times were found for CO2 and N2O carrier gases.

  14. Separation of polyprenol and dolichol by monolithic silica capillary column chromatography.

    PubMed

    Bamba, Takeshi; Fukusaki, Eiiciro; Minakuchi, Hiroshi; Nakazawa, Yoshihisa; Kobayashi, Akio

    2005-10-01

    We attempted an analysis of naturally occurring polyprenol and dolichol using a monolithic silica capillary column in HPLC. First, the separation of the polyprenol mixture alone was performed using a 250 x 0.2 mm inner diameter (ID) octadecylsilyl (ODS)-monolithic silica capillary column. The resolution of the separation between octadecaprenol (prenol 18) and nonadecaprenol (prenol 19) exceeded by >or=2-fold the level recorded when using a conventional ODS-silica particle-packed column (250 x 4.6 mm ID) under the same elution conditions. Next, the mixture of the prenol type (polyprenol) and dolichol type (dihydropolyprenol) was subjected to this capillary HPLC system, and the separation of each homolog was successfully achieved. During the analysis of polyprenol fraction derived from Eucommia ulmoides leaves, dolichols were found as a single peak, including all-trans-polyprenol and cis-polyprenol previously identified. This sensitive high-resolution system is very useful for the analysis of compounds that are structurally close to polyprenols and dolichols and that have a low content.

  15. Control of selectivity via nanochemistry: monolithic capillary column containing hydroxyapatite nanoparticles for separation of proteins and enrichment of phosphopeptides.

    PubMed

    Krenkova, Jana; Lacher, Nathan A; Svec, Frantisek

    2010-10-01

    New monolithic capillary columns with embedded commercial hydroxyapatite nanoparticles have been developed and used for protein separation and selective enrichment of phosphopeptides. The rod-shaped hydroxyapatite nanoparticles were incorporated into the poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) monolith by simply admixing them in the polymerization mixture followed by in situ polymerization. The effect of percentages of monomers and hydroxyapatite nanoparticles in the polymerization mixture on the performance of the monolithic column was explored in detail. We found that the loading capacity of the monolith is on par with other hydroxyapatite separation media. However, the speed at which these columns can be used is higher due to the fast mass transport. The function of the monolithic columns was demonstrated with the separations of a model mixture of proteins including ovalbumin, myoglobin, lysozyme, and cytochrome c as well as a monoclonal antibody and its aggregates with protein A. Selective enrichment and MALDI/MS characterization of phosphopeptides fished-out from complex peptide mixtures of ovalbumin, α-casein, and β-casein digests were also achieved using the hydroxyapatite monolith.

  16. Preparation of cyclodextrin-modified monolithic hybrid columns for the fast enantioseparation of hydroxy acids in capillary liquid chromatography.

    PubMed

    Szwed, Kamila; Ou, Junjie; Huang, Guang; Lin, Hui; Liu, Zhongshan; Wang, Hongwei; Zou, Hanfa

    2016-03-01

    Cyclodextrins and their derivatives are one of the most common and successful chiral selectors. However, there have been few publications about the use of cyclodextrin-modified monoliths. In this study, organic hybrid monoliths were prepared by the immobilization of derivatized β-cyclodextrin alone or with l-2-allylglycine hydrochloride to the polyhedral oligomeric silsesquioxane methacryl substituted monolith. The main topic of this study is a combined system with dual chiral selectors (l-2-allylglycine hydrochloride and β-cyclodextrin) as monolithic chiral stationary phase. The effect of l-2-allylglycine hydrochloride concentration on enantioseparation was investigated. The enantioseparation of the four acidic compounds with resolutions up to 2.87 was achieved within 2.5 min on the prepared chiral monolithic column in capillary liquid chromatography. Moreover, the possible mechanism of enantioseparation was discussed. PMID:27027591

  17. Preparation and evaluation of rigid porous polyacrylamide-based strong cation-exchange monolithic columns for capillary electrochromatography.

    PubMed

    Dong, Jing; Ou, Junjie; Dong, Xiaoli; Wu, Renan; Ye, Mingliang; Zou, Hanfa

    2007-11-01

    A CEC monolithic column with strong cation-exchange (SCX) stationary phase based on hydrophilic monomers was prepared by in situ polymerization of acrylamide, methylenebisacrylamide, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in a complete organic binary porogenic solvent consisting of DMSO and dodecanol. The sulfonic groups provided by the monomer AMPS on the surface of the stationary phase generate an EOF from anode to cathode, and serve as an SCX stationary phase at the same time. The monolithic stationary phase exhibited normal-phase chromatographic behavior for neutral analytes. For charged analytes, electrostatic interaction/repulsion with the monolith was observed. The strong SCX monolithic column has been successfully employed in the electrochromatographic separation of basic drugs, peptides, and alkaloids extracted from natural products.

  18. Preparation and evaluation of rigid porous polyacrylamide-based strong cation-exchange monolithic columns for capillary electrochromatography.

    PubMed

    Dong, Jing; Ou, Junjie; Dong, Xiaoli; Wu, Renan; Ye, Mingliang; Zou, Hanfa

    2007-11-01

    A CEC monolithic column with strong cation-exchange (SCX) stationary phase based on hydrophilic monomers was prepared by in situ polymerization of acrylamide, methylenebisacrylamide, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in a complete organic binary porogenic solvent consisting of DMSO and dodecanol. The sulfonic groups provided by the monomer AMPS on the surface of the stationary phase generate an EOF from anode to cathode, and serve as an SCX stationary phase at the same time. The monolithic stationary phase exhibited normal-phase chromatographic behavior for neutral analytes. For charged analytes, electrostatic interaction/repulsion with the monolith was observed. The strong SCX monolithic column has been successfully employed in the electrochromatographic separation of basic drugs, peptides, and alkaloids extracted from natural products. PMID:17924588

  19. Preparation and characterization of a molecularly imprinted monolithic column for pressure-assisted CEC separation of nitroimidazole drugs.

    PubMed

    Liao, Sulan; Wang, Xiaochun; Lin, Xucong; Xie, Zenghong

    2010-08-01

    A polymethacrylate-based molecularly imprinted monolithic column bearing mixed functional monomers, using non-covalent imprinting approach, was designed for the rapid separation of nitroimidazole compounds. The new monolithic column has been prepared via simple in situ polymerization of 2-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and ethylene dimethacrylate, using (S)-ornidazole ((S)-ONZ) as template in a binary porogenic mixture consisting of toluene and dodecanol. The composition of the polymerization mixture was systematically altered and optimized by altering the amount of monomers as well as the composition of the porogenic solvent. The column performance was evaluated in pressure-assisted CEC mode. Separation conditions such as pH, voltage, amount of organic modifier and salt concentration were studied. The optimized monolithic column resulted in excellent separation of a group of structurally related nitroimidazole drugs within 10 min in isocratic elution condition. Column efficiencies of 99 000, 80 000, 103 000, 60 000 and 99 000 plates/m were obtained for metronidazole, secnidazole, ronidazole, tinidazole and dimetridazole, respectively. Parallel experiments were carried out using molecularly imprinted and non-imprinted capillary columns. The separation might be the result of combined effects including hydrophobic, hydrogen bonding and the imprinting cavities on the (S)-ONZ-imprinted monolithic column. PMID:20661943

  20. Advances in the development of organic polymer monolithic columns and their applications in food analysis--a review.

    PubMed

    Jandera, Pavel

    2013-10-25

    Monolithic continuous separation media are gradually finding their way to sample pre-treatment, isolation, enrichment and final analytical separations of a plethora of compounds, occurring as food components, additives or contaminants, including pharmaceuticals, pesticides and toxins, which have traditionally been the domain of particulate chromatographic materials. In the present review, recent advances in the technology of monolithic columns and the applications in food analysis are addressed. Silica-based monoliths are excellent substitutes to conventional particle-packed columns, improving the speed of analysis for low-molecular weight compounds, due to their excellent efficiency and high permeability. These properties have been recently appreciated in two-dimensional HPLC, where the performance in the second dimension is of crucial importance. Organic-polymer monoliths in various formats provide excellent separations of biopolymers. Thin monolithic disks or rod columns are widely employed in isolation, purification and pre-treatment of sample containing proteins, peptides or nucleic acid fragments. Monolithic capillaries were originally intended for use in electrochromatography, but are becoming more frequently used for capillary and micro-HPLC. Monoliths are ideal highly porous support media for immobilization or imprinting template molecules, to provide sorbents for shape-selective isolation of target molecules from various matrices occurring in food analysis. The separation efficiency of organic polymer monoliths for small molecules can be significantly improved by optimization of polymerization approach, or by post-polymerization modification. This will enable full utilization of a large variety of available monomers to prepare monoliths with chemistry matching the needs of selectivity of separations of various food samples containing even very polar or ionized compounds.

  1. [Ion-pair chromatography-indirect ultraviolet detection for determination of tetraethyl ammonium using a monolithic column and a packed column].

    PubMed

    Zou, Chunmiao; Zhang, Xiaodong; Yu, Hong; Guan, Chao; Wang, Miaoyu

    2015-07-01

    Two methods were developed for the determination of tetraethyl ammonium by ion-pair chromatography-indirect ultraviolet detection using a monolithic column and a packed column with ionic liquid as additive in mobile phase. Chromatographic separations were performed on a monolithic column and a packed column both on reversed phase using imidazolium ionic liquid aqueous solution-ion-pair reagent-organic solvent as mobile phase. The effects of the background ultraviolet absorption reagent, detection wavelength, ion-pair reagent, organic solvent, column temperature and flow rate on the determination of tetraethyl ammonium were investigated. The difference between the two chromatographic columns was compared and the retention rules were discussed. Under the optimized chromatographic conditions, for tetraethyl ammonium on monolithic column and packed column, the retention times were 2.40 and 3.02 min; the detection limits (S/N=3), 0.04 and 0.07 mg/L; the RSDs (n = 5) for peak areas, 0.16% and 0.11%; and the RSDs (n=5) for retention times, 0.02% and 0.01%, respectively. The two methods have been successfully applied to the determination of tetraethyl ammonium ionic liquids synthesized by laboratory. The recoveries of the tetraethyl ammonium after spiking were 98.2% and 99.1%, respectively. The two methods can meet the requirements for the quantitative analysis of tetraethyl ammonium.

  2. DATA QUALITY OBJECTIVE SUMMARY REPORT FOR THE 105 K EAST ION EXCHANGE COLUMN MONOLITH

    SciTech Connect

    JOCHEN, R.M.

    2007-08-02

    The 105-K East (KE) Basin Ion Exchange Column (IXC) cells, lead caves, and the surrounding vault are to be removed as necessary components in implementing ''Hanford Federal Facility Agreement and Consent Order'' (Ecology et al. 2003) milestone M-034-32 (Complete Removal of the K East Basin Structure). The IXCs consist of six units located in the KE Basin, three in operating positions in cells and three stored in a lead cave. Methods to remove the IXCs from the KE Basin were evaluated in KBC-28343, ''Disposal of K East Basin Ion Exchange Column Evaluation''. The method selected for removal was grouting the six IXCs into a single monolith for disposal at the Environmental Restoration Disposal Facility (ERDF). Grout will be added to the IXC cells, IXC lead caves containing spent IXCs, and in the spaces between the lead cave walls and metal skin, to immobilize the contaminants, provide self-shielding, minimize void space, and provide a structurally stable waste form. The waste to be offered for disposal is the encapsulated monolith defined by the exterior surfaces of the vault and the lower surface of the underlying slab. This document presents summary of the data quality objective (DQO) process establishing the decisions and data required to support decision-making activities for the disposition of the IXC monolith. The DQO process is completed in accordance with the seven-step planning process described in EPA QA/G-4, ''Guidance for the Data Quality Objectives Process'', which is used to clarify and study objectives; define the appropriate type, quantity, and quality of data; and support defensible decision-making. The DQO process involves the following steps: (1) state the problem; (2) identify the decision; (3) identify the inputs to the decision; (4) define the boundaries of the study; (5) develop a decision rule (DR); (6) specify tolerable limits on decision errors; and (7) optimize the design for obtaining data.

  3. DATA QUALITY OBJECTIVES SUMMARY REPORT FOR THE 105K EAST BASIN ION EXCHANGE COLUMN MONOLITH

    SciTech Connect

    JOCHEN, R.M.

    2007-02-07

    The 105-K East (KE) Basin Ion Exchange Column (IXC) cells, lead caves, and the surrounding vault are to be removed as necessary components in implementing ''Hanford Federal Facility Agreement and Consert Order'' (Ecology et al. 2003) milestone M-034-32 (Complete Removal of the K East Basin Structure). The IXCs consist of six units located in the KE Basin, three in operating positions in cells and three stored in a lead cave. Methods to remove the IXCs from the KE Basin were evaluated in KBC-28343, ''Disposal of K East Basin Ion Exchange Column Evaluation''. The method selected for removal was grouting of the six IXCs into a single monolith for disposal at the Environmental Restoration Disposal Facility (ERDF). Grout will be added to the IXC cells, IXC lead caves containing spent IXCs, and in the spaces between to immobilize the contaminants, provide self-shielding, minimize void space, and provide a structurally stable waste form. The waste to be offered for disposal is the encapsulated monolith defined by the exterior surfaces of the vault and the lower surface of the underlying slab. This document presents a summary of the data quality objective (DQO) process establishing the decisions and data required to support decision-making activities for disposition of the IXC monolith. The DQO process is completed in accordance with the seven-step planning process described in EPA QA/G-4, ''Guidance for the Data Quality Objectives Process'', which is used to clarify and study objectives; define the appropriate type, quantity, and quality of data; and support defensible decision-making. The DQO process involves the following steps: (1) state the problem; (2) identify the decision; (3) identify the inputs to the decision; (4) define the boundaries of the study; (5) develop a decision rule (DR); (6) specify tolerable limits on decision errors; and (7) optimize the design for obtaining data.

  4. Mass transfer kinetic mechanism in monolithic columns and application to the characterization of new research monolithic samples with different average pore sizes.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2009-06-01

    A general reduced HETP (height equivalent to a theoretical plate) equation is proposed that accounts for the mass transfer of a wide range of molecular weight compounds in monolithic columns. The detailed derivatization of each one of the individual and independent mass transfer contributions (longitudinal diffusion, eddy dispersion, film mass transfer resistance, and trans-skeleton mass transfer resistance) is discussed. The reduced HETPs of a series of small molecules (phenol, toluene, acenaphthene, and amylbenzene) and of a larger molecule, insulin, were measured on three research grade monolithic columns (M150, M225, M350) having different average pore size (approximately 150, 225, and 350 A, respectively) but the same dimension (100 mm x 4.6 mm). The first and second central moments of 2 muL samples were measured and corrected for the extra-column contributions. The h data were fitted to the new HETP equation in order to identify which contribution controls the band broadening in monolithic columns. The contribution of the B-term was found to be negligible compared to that of the A-term, even at very low reduced velocities (nu<1). At moderate velocities (1column. Experimental chromatograms exhibited variable degrees of systematic peak fronting, depending on the column studied. The heterogeneity of the distribution of eluent velocities from the column center to its wall (average 5%) is the source of this peak fronting. At high reduced velocities (nu>5), the C-term of the monolithic columns is controlled by film mass transfer resistance between the eluent circulating in the large throughpores and the eluent stagnant inside the thin porous skeleton. The experimental Sherwood number measured on the monolith columns increases from 0.05 to 0.22 while the adsorption energy increases by nearly 6 k

  5. Green approach using monolithic column for simultaneous determination of coformulated drugs.

    PubMed

    Yehia, Ali M; Mohamed, Heba M

    2016-06-01

    Green chemistry and sustainability is now entirely encompassed across the majority of pharmaceutical companies and research labs. Researchers' attention is careworn toward implementing the green analytical chemistry principles for more eco-friendly analytical methodologies. Solvents play a dominant role in determining the greenness of the analytical procedure. Using safer solvents, the greenness profile of the methodology could be increased remarkably. In this context, a green chromatographic method has been developed and validated for the simultaneous determination of phenylephrine, paracetamol, and guaifenesin in their ternary pharmaceutical mixture. The chromatographic separation was carried out using monolithic column and green solvents as mobile phase. The use of monolithic column allows efficient separation protocols at higher flow rates, which results in short time of analysis. Two-factor three-level experimental design was used to optimize the chromatographic conditions. The greenness profile of the proposed methodology was assessed using eco-scale as a green metrics and was found to be an excellent green method with regard to the usage and production of hazardous chemicals and solvents, energy consumption, and amount of produced waste. The proposed method improved the environmental impact without compromising the analytical performance criteria and could be used as a safer alternate for the routine analysis of the studied drugs. PMID:27062581

  6. Green approach using monolithic column for simultaneous determination of coformulated drugs.

    PubMed

    Yehia, Ali M; Mohamed, Heba M

    2016-06-01

    Green chemistry and sustainability is now entirely encompassed across the majority of pharmaceutical companies and research labs. Researchers' attention is careworn toward implementing the green analytical chemistry principles for more eco-friendly analytical methodologies. Solvents play a dominant role in determining the greenness of the analytical procedure. Using safer solvents, the greenness profile of the methodology could be increased remarkably. In this context, a green chromatographic method has been developed and validated for the simultaneous determination of phenylephrine, paracetamol, and guaifenesin in their ternary pharmaceutical mixture. The chromatographic separation was carried out using monolithic column and green solvents as mobile phase. The use of monolithic column allows efficient separation protocols at higher flow rates, which results in short time of analysis. Two-factor three-level experimental design was used to optimize the chromatographic conditions. The greenness profile of the proposed methodology was assessed using eco-scale as a green metrics and was found to be an excellent green method with regard to the usage and production of hazardous chemicals and solvents, energy consumption, and amount of produced waste. The proposed method improved the environmental impact without compromising the analytical performance criteria and could be used as a safer alternate for the routine analysis of the studied drugs.

  7. [Preparation of a reversed-phase capillary monolithic column and its application in the separation of polypeptide mixtures].

    PubMed

    Xie, Jingxin; Bi, Kaishun; Qian, Xiaohong; Zuang, Yangiun

    2009-03-01

    Capillary monolithic columns (75 microm i.d.) were prepared by the copolymerization of lauryl methacrylate as the basic monomer, ethylene dimethacrylate as the cross-linking agent and 1-dodecyl alcohol, 1,4-butanediol and dimethyl sulfoxide as the porogenic mixture. The synthetic stationary phases had better mechanical properties and chemical stabilities. A series of characterization and evaluations were performed on the capillary monolithic columns including the scanning electron microscope (SEM) images, the influences of pressure and the effects on the separation of peptide mixtures by changing the proportions of the porogen solution and cross-linking agent. The final prescription ciontained 15% (w/w) monomer, 15% (w/ w) cross-linking agent, and 70% (w/w) porogenic agent. Then the solution was heated at 70 1C for 24 h. The test of relationship between column length and back pressure showed that the capillary monolithic columns prepared have superior permeability, so a longer column can be used to improve the effects of separation. The prepared capillary monolithic columns are fitted on the nano-scale high performance liquid chromatography for the separation of tryptic digests of bovine serum albumin (BSA) and human plasma samples, and better results have been obtained.

  8. Possibilities of retention prediction in fast gradient liquid chromatography. Part 3: Short silica monolithic columns.

    PubMed

    Jandera, Pavel; Hájek, Tomáš

    2015-09-01

    We studied possibilities of prediction of the gradient elution data for alkylbenzenes, flavones and phenolic acids on two short octadecyl silica gel monolithic columns, namely a Chromolith Flash C18, 25×4.6mm, and a "new generation" Chromolith High Resolution C18, 50×4.6mm, in fast 1-2min gradients. With fixed short gradient times and varying gradient ranges of acetonitrile concentration in water, high flow rates of the mobile phase (3-5mL/min) could be used. The gradient elution data were predicted from four gradient models based on two-parameter and three-parameter isocratic retention equations. Various gradient retention models can be used for prediction of chromatograms and optimization of separation within a fixed gradient time. A two-parameter log-log model introduced in 1974 and a three-parameter model introduced in 1980 provided slightly more accurate prediction than the Linear Solvent Strength (LSS) semi-logarithmic two-parameter model, most frequently used in reversed-phase LC. A three-parameter model introduced in 1978 provided slightly improved accuracy of prediction of gradient data with respect to two-parameter models, in contrast to another, more recent three-parameter empirical model introduced in 2010 (which failed for gradients starting at a non-zero concentration of acetonitrile). Both a longer (5cm) and more efficient Chromolith HR column and a shorter (2.5cm) slightly less efficient Chromolith Flash column provide useful separations in fast gradients (1-2min) at high flow rates (3.5-5mL/min), especially in second dimension of two-dimensional LC×LC, in combination with HILIC separation on monolithic microcolumn in D1. PMID:26239700

  9. Molecularly imprinted macroporous monoliths for solid-phase extraction: Effect of pore size and column length on recognition properties.

    PubMed

    Vlakh, E G; Stepanova, M A; Korneeva, Yu M; Tennikova, T B

    2016-09-01

    The series of macroporous monolithic molecularly imprinted monoliths differed by pore size, column length (volume) and amount of template used for imprinting was synthesized using methacrylic acid and glycerol dimethacrylate as co-monomers and antibiotic ciprofloxacin as a template. The prepared monoliths were characterized regarding to their permeability, pore size, porosity, and resistance to the flow of a mobile phase. The surface morphology was also analyzed. The slight dependence of imprinting factor on flow rate, as well as its independence on pore size of macroporous molecularly imprinted monolithic media was observed. The column obtained at different conditions exhibited different affinity of ciprofloxacin to the imprinted sites that was characterized with Kdiss values in the range of 10(-5)-10(-4)M. The solid-phase extraction of ciprofloxacin from such biological liquids as human blood serum, human urine and cow milk serum was performed using the developed monolithic columns. In all cases, the extraction was found to be 95.0-98.6%. Additionally, the comparison of extraction of three fluoroqinolone analogues, e.g. ciprofloxacin, levofloxacin and moxifloxacin, from human blood plasma was carried out. Contrary to ciprofloxacin extracted with more than 95%, this parameter did not exceed 40% for its analogues. PMID:27433985

  10. Preparation, characterization and application of molecularly imprinted monolithic column for hesperetin.

    PubMed

    Shao, Huikai; Zhao, Lingguo; Chen, Jian; Zhou, Haitao; Huang, Shuting; Li, Kang

    2015-01-01

    The molecularly imprinted solid-phase extraction (MISPE) monolithic column coupled with high-performance liquid chromatography (HPLC) was firstly developed for the extraction of hesperetin in the flesh of Citrus reticulata cv. Chachiensis, which is a traditional Chinese medicine (TCM). The molecularly imprinted polymers (MIPs) have been prepared by a thermal polymerization method using hesperetin as the template, acrylamide (AM) as functional monomer and ethylene glycol dimethacrylamide (EGDMA) as cross-linker in the mixed porogen of methanol, toluene and dodecanol. The prepared MIPs were characterized in detail by SEM and FTIR. The results confirmed the uniform and open structure of network skeleton with large flow-through pores. The influence of synthesis conditions on the specific recognition properties of hesperetin MIPs were also investigated systematically. The results showed that high adsorption capacity and good selectivity of MIPs were achieved when using non-imprinted polymer monolith (NIP) and structure similarly compound rutin as references. Furthermore, several parameters of the MISPE method have been optimized, and then it was successfully applied to the extraction of hesperetin from the flesh of Citrus reticulata cv. Chachiensis. Good gathering and impurity removing ability of prepared MIP were demonstrated. The MISPE method was proven to be a potentially competitive technique for separation and cleanup of hesperetin in complex TCM with satisfied recovery (90.8 ± 3.2%) and good precision (RSD = 6.48%).

  11. Laser Scanning of a Monolithic Column during Processing in Middle Egypt

    NASA Astrophysics Data System (ADS)

    Ajioka, O.; Hori, Y.

    2011-09-01

    From ancient quarries around Akoris in Middle Egypt, which belong to the Ptolemaic and Roman periods, the stone blocks could be carried to the working area located in the outside of the city. Those blocks included a giant monolithic column measured approximately 14m in length, which had been cracked for reasons unknown and must have contributed to disuse of monolith. The first deal is a comparison of plans drawn by the point clouds by laser scanning with those coming from plane-tabling, which had been one of popular methods for measuring in the last century. This part shows how the laser scanning technology is useful in far better measuring and documentation of the site. The second discuss is about a detailed assessment of the procedure of processing through the observation of chisel marks and the detail analysis about the 3 dimensional data. In the result, we are succeed to show the restoration of the procedure of the proceedings using guidelines and a wooden curve since we concentrate attention on the point of abstracting the centre line and shaving the surface into the round shape.

  12. Acrylate ester-based monolithic columns for capillary electrochromatography separation of triacylglycerols in vegetable oils.

    PubMed

    Lerma-García, M J; Vergara-Barberán, M; Herrero-Martínez, J M; Simó-Alfonso, E F

    2011-10-21

    A simple and reliable method for the evaluation of triacylglycerols (TAGs) in vegetable oils by capillary electrochromatography (CEC) with UV-Vis detection, using octadecyl acrylate (ODA) ester-based monolithic columns, has been developed. The percentages of the porogenic solvents in the polymerization mixture, and the mobile phase composition, were optimized. The optimum monolith was obtained at the following ratios: 40:60% (wt/wt) monomers/porogens, 60:40% (wt/wt) ODA/1,3-butanediol diacrylate and 23:77% (wt/wt) 1,4-butanediol/1-propanol (14 wt% 1,4-butanediol in the polymerization mixture). A satisfactory resolution between TAGs was achieved in less than 12 min with a 65:35 (v/v) acetonitrile/2-propanol mixture containing 5 mM ammonium acetate. The method was applied to the analysis of TAGs of vegetable oil samples. Using linear discriminant analysis of the CEC TAG profiles, the vegetable oils belonging to six different botanical origins (corn, extra virgin olive, hazelnut, peanut, soybean and sunflower) were correctly classified with an excellent resolution among all the categories.

  13. Preparation, characterization and application of molecularly imprinted monolithic column for hesperetin.

    PubMed

    Shao, Huikai; Zhao, Lingguo; Chen, Jian; Zhou, Haitao; Huang, Shuting; Li, Kang

    2015-01-01

    The molecularly imprinted solid-phase extraction (MISPE) monolithic column coupled with high-performance liquid chromatography (HPLC) was firstly developed for the extraction of hesperetin in the flesh of Citrus reticulata cv. Chachiensis, which is a traditional Chinese medicine (TCM). The molecularly imprinted polymers (MIPs) have been prepared by a thermal polymerization method using hesperetin as the template, acrylamide (AM) as functional monomer and ethylene glycol dimethacrylamide (EGDMA) as cross-linker in the mixed porogen of methanol, toluene and dodecanol. The prepared MIPs were characterized in detail by SEM and FTIR. The results confirmed the uniform and open structure of network skeleton with large flow-through pores. The influence of synthesis conditions on the specific recognition properties of hesperetin MIPs were also investigated systematically. The results showed that high adsorption capacity and good selectivity of MIPs were achieved when using non-imprinted polymer monolith (NIP) and structure similarly compound rutin as references. Furthermore, several parameters of the MISPE method have been optimized, and then it was successfully applied to the extraction of hesperetin from the flesh of Citrus reticulata cv. Chachiensis. Good gathering and impurity removing ability of prepared MIP were demonstrated. The MISPE method was proven to be a potentially competitive technique for separation and cleanup of hesperetin in complex TCM with satisfied recovery (90.8 ± 3.2%) and good precision (RSD = 6.48%). PMID:25910048

  14. Behavior of short silica monolithic columns in high pressure gas chromatography.

    PubMed

    Maniquet, Adrien; Bruyer, Nicolas; Raffin, Guy; Baco-Antoniali, Franck; Demesmay, Claire; Dugas, Vincent; Randon, Jérôme

    2016-08-19

    In order to analyze light hydrocarbons mixtures with silica monolithic columns, a conventional gas chromatograph was modified to work with carrier gas pressure as high as 60bar. To understand hydrodynamic flow and retention with short columns (less than 30cm), special attention was required due to the temperature difference between the oven area and the FID detector which contain a significant length of the column. Efficiency and selectivity using various carrier gases (helium, nitrogen and carbon dioxide) at different inlet pressure for different oven temperature were studied. Carrier gas nature was a very significant parameter: on one side, linked to adsorption mechanism for gases like nitrogen and carbon dioxide onto the stationary phase modifying retention and selectivity, on the other side in relation to the minimum theoretical plate height which was as low as 15μm (66 000 platem(-1)) using carbon dioxide as carrier gas. The chromatographic system was then used to separate methane, ethane, ethylene, acetylene, propane, cyclopropane, and butane in less than 30s. PMID:27432790

  15. Chromatographic selectivity of poly(alkyl methacrylate-co-divinylbenzene) monolithic columns for polar aromatic compounds by pressure-driven capillary liquid chromatography.

    PubMed

    Lin, Shu-Ling; Wang, Chih-Chieh; Fuh, Ming-Ren

    2016-10-01

    In this study, divinylbenzene (DVB) was used as the cross-linker to prepare alkyl methacrylate (AlMA) monoliths for incorporating π-π interactions between the aromatic analytes and AlMA-DVB monolithic stationary phases in capillary LC analysis. Various AlMA/DVB ratios were investigated to prepare a series of 30% AlMA-DVB monolithic stationary phases in fused-silica capillaries (250-μm i.d.). The physical properties (such as porosity, permeability, and column efficiency) of the synthesized AlMA-DVB monolithic columns were investigated for characterization. Isocratic elution of phenol derivatives was first employed to evaluate the suitability of the prepared AlMA-DVB columns for small molecule separation. The run-to-run (0.16-1.20%, RSD; n = 3) and column-to-column (0.26-2.95%, RSD; n = 3) repeatabilities on retention times were also examined using the selected AlMA-DVB monolithic columns. The π-π interactions between the aromatic ring and the DVB-based stationary phase offered better recognition on polar analytes with aromatic moieties, which resulted in better separation resolution of aromatic analytes on the AlMA-DVB monolithic columns. In order to demonstrate the capability of potential environmental and/or food safety applications, eight phenylurea herbicides with single benzene ring and seven sulfonamide antibiotics with polyaromatic moieties were analyzed using the selected AlMA-DVB monolithic columns.

  16. Chromatographic selectivity of poly(alkyl methacrylate-co-divinylbenzene) monolithic columns for polar aromatic compounds by pressure-driven capillary liquid chromatography.

    PubMed

    Lin, Shu-Ling; Wang, Chih-Chieh; Fuh, Ming-Ren

    2016-10-01

    In this study, divinylbenzene (DVB) was used as the cross-linker to prepare alkyl methacrylate (AlMA) monoliths for incorporating π-π interactions between the aromatic analytes and AlMA-DVB monolithic stationary phases in capillary LC analysis. Various AlMA/DVB ratios were investigated to prepare a series of 30% AlMA-DVB monolithic stationary phases in fused-silica capillaries (250-μm i.d.). The physical properties (such as porosity, permeability, and column efficiency) of the synthesized AlMA-DVB monolithic columns were investigated for characterization. Isocratic elution of phenol derivatives was first employed to evaluate the suitability of the prepared AlMA-DVB columns for small molecule separation. The run-to-run (0.16-1.20%, RSD; n = 3) and column-to-column (0.26-2.95%, RSD; n = 3) repeatabilities on retention times were also examined using the selected AlMA-DVB monolithic columns. The π-π interactions between the aromatic ring and the DVB-based stationary phase offered better recognition on polar analytes with aromatic moieties, which resulted in better separation resolution of aromatic analytes on the AlMA-DVB monolithic columns. In order to demonstrate the capability of potential environmental and/or food safety applications, eight phenylurea herbicides with single benzene ring and seven sulfonamide antibiotics with polyaromatic moieties were analyzed using the selected AlMA-DVB monolithic columns. PMID:27639150

  17. Rapid determination of amino acids in biological samples using a monolithic silica column.

    PubMed

    Song, Yanting; Funatsu, Takashi; Tsunoda, Makoto

    2012-05-01

    A high-performance liquid chromatography method in which fluorescence detection is used for the simultaneous determination of 21 amino acids is proposed. Amino acids were derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) and then separated on a monolithic silica column (MonoClad C18-HS, 150 mm×3 mm i.d.). A mixture of 25 mM citrate buffer containing 25 mM sodium perchlorate (pH 5.5) and acetonitrile was used as the mobile phase. We found that the most significant factor in the separation was temperature, and a linear temperature gradient from 30 to 49°C was used to control the column temperature. The limits of detection and quantification for all amino acids ranged from 3.2 to 57.2 fmol and 10.8 to 191 fmol, respectively. The calibration curves for the NBD-amino acid had good linearity within the range of 40 fmol to 40 pmol when 6-aminocaproic acid was used as an internal standard. Using only conventional instruments, the 21 amino acids could be analyzed within 10 min. This method was found to be suitable for the quantification of the contents of amino acids in mouse plasma and adrenal gland samples.

  18. Fabrication of zeolitic imidazolate framework-8-methacrylate monolith composite capillary columns for fast gas chromatographic separation of small molecules.

    PubMed

    Yusuf, Kareem; Badjah-Hadj-Ahmed, Ahmed Yacine; Aqel, Ahmad; ALOthman, Zeid Abdullah

    2015-08-01

    A composite zeolitic imidazolate framework-8 (ZIF-8) with a butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.) was fabricated to enhance the separation efficiency of methacrylate monoliths toward small molecules using conventional low-pressure gas chromatography in comparison with a neat butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.). The addition of 10mgmL(-1) ZIF-8 micro-particles increased the BET surface area of BuMA-co-EDMA by 3.4-fold. A fast separation of five linear alkanes in 36s with high resolution (Rs≥1.3) was performed using temperature program. Isothermal separation of the same sample also showed a high efficiency (3315platesm(-1) for octane) at 0.89min. Moreover, the column was able to separate skeletal isomers, such as iso-octane/octane and 2-methyl octane/nonane. In addition, an iso-butane/iso-butylene gas mixture was separated at ambient temperature. Comparison with an open tubular TR-5MS column (30m long×250μm i.d.) revealed the superiority of the composite column in separating the five-membered linear alkane mixture with 4-5 times increase in efficiency and a total separation time of 0.89min instead of 4.67min. A paint thinner sample was fully separated using the composite column in 2.43min with a good resolution (Rs≥0.89). The perfect combination between the polymeric monolith, with its high permeability, and ZIF-8, with its high surface area and flexible 0.34nm pore openings, led to the fast separation of small molecules with high efficiency and opened a new horizon in GC applications.

  19. Fabrication of zeolitic imidazolate framework-8-methacrylate monolith composite capillary columns for fast gas chromatographic separation of small molecules.

    PubMed

    Yusuf, Kareem; Badjah-Hadj-Ahmed, Ahmed Yacine; Aqel, Ahmad; ALOthman, Zeid Abdullah

    2015-08-01

    A composite zeolitic imidazolate framework-8 (ZIF-8) with a butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.) was fabricated to enhance the separation efficiency of methacrylate monoliths toward small molecules using conventional low-pressure gas chromatography in comparison with a neat butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.). The addition of 10mgmL(-1) ZIF-8 micro-particles increased the BET surface area of BuMA-co-EDMA by 3.4-fold. A fast separation of five linear alkanes in 36s with high resolution (Rs≥1.3) was performed using temperature program. Isothermal separation of the same sample also showed a high efficiency (3315platesm(-1) for octane) at 0.89min. Moreover, the column was able to separate skeletal isomers, such as iso-octane/octane and 2-methyl octane/nonane. In addition, an iso-butane/iso-butylene gas mixture was separated at ambient temperature. Comparison with an open tubular TR-5MS column (30m long×250μm i.d.) revealed the superiority of the composite column in separating the five-membered linear alkane mixture with 4-5 times increase in efficiency and a total separation time of 0.89min instead of 4.67min. A paint thinner sample was fully separated using the composite column in 2.43min with a good resolution (Rs≥0.89). The perfect combination between the polymeric monolith, with its high permeability, and ZIF-8, with its high surface area and flexible 0.34nm pore openings, led to the fast separation of small molecules with high efficiency and opened a new horizon in GC applications. PMID:26141277

  20. Separation of proteins by cation-exchange sequential injection chromatography using a polymeric monolithic column.

    PubMed

    Masini, Jorge Cesar

    2016-02-01

    Since sequential injection chromatography (SIC) emerged in 2003, it has been used for separation of small molecules in diverse samples, but separations of high molar mass compounds such as proteins have not yet been described. In the present work a poly(glycidyl methacrylate-co-ethylene dimethacrylate) (GMA-co-EDMA) monolithic column was prepared by free radical polymerization inside a 2.1-mm-i.d. activated fused silica-lined stainless steel tubing and modified with iminodiacetic acid (IDA). The column was prepared from a mixture of 24% GMA, 16% EDMA, 20% cyclohexanol, and 40% 1-dodecanol (all% as w/w) containing 1% of azobisisobutyronitrile (AIBN) (in relation to monomers). Polymerization was done at 60 °C for 24 h. The polymer was modified with 1.0 M IDA (in 2 M Na2CO3, pH 10.5) at 80 °C for 16 h. Separation of myoglobin, ribonuclease A, cytochrome C, and lysozyme was achieved at pH 7.0 (20 mM KH2PO4/K2HPO4) using a salt gradient (NaCl). Myoglobin was not retained, and the other proteins were separated by a gradient of NaCl created inside the holding coil (4 m of 0.8-mm-i.d. PTFE tubing) by sequential aspiration of 750 and 700 μL of 0.2 and 0.1 M NaCl, respectively. As the flow was reversed toward the column (5 μL s(-1)) the interdispersion of these solutions created a reproducible gradient which separated the proteins in 10 min, with the following order of retention: ribonuclease A < cytochrome C < lysozyme. The elution order was consistent with a cation-exchange mechanism as the retention increased with the isoelectric points.

  1. High-throughput purification of double-stranded RNA molecules using convective interaction media monolithic anion exchange columns.

    PubMed

    Romanovskaya, Alesia; Sarin, L Peter; Bamford, Dennis H; Poranen, Minna M

    2013-02-22

    Recent advances in the field of RNA interference and new cost-effective approaches for large-scale double-stranded RNA (dsRNA) synthesis have fuelled the demand for robust high-performance purification techniques suitable for dsRNA molecules of various lengths. To address this issue, we developed an improved dsRNA purification method based on anion exchange chromatography utilizing convective interaction media (CIM) monolithic columns. To evaluate column performance we synthesized a selection of dsRNA molecules (58-1810 bp) in a one-step enzymatic reaction involving bacteriophage T7 DNA-dependent RNA polymerase and phi6 RNA-dependent RNA polymerase. In addition, small interfering RNAs (siRNAs) of 25-27 bp were generated by Dicer digestion of the genomic dsRNA of bacteriophage phi6. We demonstrated that linearly scalable CIM monolithic quaternary amine (QA) columns can be used as a fast and superior alternative to standard purification methods (e.g. LiCl precipitation) to obtain highly pure dsRNA preparations. The impurities following Dicer treatment were quickly and efficiently removed with the QA CIM monolithic column, yielding siRNA molecules of high purity suitable for potential therapeutic applications. Moreover, baseline separation of dsRNA molecules up to 1 kb in non-denaturing conditions was achieved.

  2. Poly(cyclooctene)-based monolithic columns for capillary high performance liquid chromatography prepared via ring-opening metathesis polymerization.

    PubMed

    Schlemmer, Bettina; Gatschelhofer, Christina; Pieber, Thomas R; Sinner, Frank M; Buchmeiser, Michael R

    2006-11-01

    Monolithic columns for capillary HPLC were prepared via ring-opening metathesis polymerization (ROMP) from cis-cyclooctene (COE), tris(cyclooct-4-enyl-1-oxy)methylsilane (CL) as monomers, 2-propanol and toluene as porogens and RuCl(2)(Py)(2)(IMesH(2))(CHC(6)H(5)) (Py=pyridine, IMesH(2)=1,3-dimesityl-4,5-dihydroimidazolin-2-ylidene) as initiator within the confines of 200 microm i.d. fused silica columns. For evaluation of the novel monolithic capillary HPLC columns, a protein standard consisting of six proteins in the molecular weight range of 5800-66000 g/mol, i.e. ribonuclease A, insulin, albumin, lysozyme, myoglobin and beta-lactoglobulin, was used. Reproducibility of synthesis was checked by determining the relative standard deviation (RSD) in retention times (t(R)), which was found to be in the range of 2.9-3.9% for all analytes. Variations in polymer kinetics were realized by adding different amounts of free pyridine and had a significant influence on the monolith's morphology, the backpressure and retention times. On the contrary, variations in monomer content and COE to CL ratio showed only minor changes on these parameters. Long-term stability of 1000 runs at 50 degrees C showed excellent stability of the columns and no significant alteration in separation performance was observed in combination with slightly decreased retention times (approx. 1.6-7.2% for all analytes).

  3. A novel application of methacrylate based short monolithic columns: concentrating Potato spindle tuber viroid from water samples.

    PubMed

    Ruščić, Jelena; Gutiérrez-Aguirre, Ion; Urbas, Lidija; Kramberger, Petra; Mehle, Nataša; Škorić, Dijana; Barut, Miloš; Ravnikar, Maja; Krajačić, Mladen

    2013-01-25

    Potato spindle tuber viroid (PSTVd) is the causal agent of a number of agriculturally important diseases. It is a single-stranded, circular and unencapsidated RNA molecule with only 356-360 nucleotides and no coding capacity. Because of its peculiar structural features, it is very stable ex vivo and it is easily transmitted mechanically by contaminated hands, tools, machinery, etc. In this work, we describe the development and optimization of a method for concentrating PSTVd using Convective Interaction Media (CIM) monolithic columns. The ion-exchange chromatography on diethylamine (DEAE) monolithic analytical column (CIMac DEAE-0.1 mL) resulted in up to 30% PSTVd recovery whilst the hydrophobic interaction chromatography on C4 monolithic analytical column (CIMac C4-0.1 mL) improved it up to 60%. This was due to the fact that the binding of the viroid to the C4 matrix was less strong than to the highly charged anion-exchange matrix and could be easier and more completely eluted under the applied chromatographic conditions. Based on these preliminary results, a C4 HLD-1 (High Ligand Density) 1 mL monolithic tube column was selected for further experiments. One-litre-water samples were mixed with different viroid quantities and loaded onto the column. By using reverse transcription quantitative polymerase chain reaction (RT-qPCR), the viroid RNA was quantified in the elution fraction (≈5 mL) indicating that 70% of the viroid was recovered and concentrated by at least two orders of magnitude. This approach will be helpful in screening irrigation waters and/or hydroponic systems' nutrient solutions for the presence of even extremely low concentrations of PSTVd.

  4. Stability and repeatability of capillary columns based on porous monoliths of poly(butyl methacrylate-co-ethylene dimethacrylate)

    PubMed Central

    Geiser, Laurent; Eeltink, Sebastiaan; Svec, Frantisek; Fréchet, Jean M.J.

    2009-01-01

    Monolithic poly(butyl methacrylate-co-ethylene dimethacrylate) capillary columns have been prepared via either thermally or photochemically initiated polymerization of the corresponding monomers and the repeatability of their preparation has been explored. Three separate batches of five columns each were prepared using thermal and photochemical initiation for a total of thirty columns. All thirty capillary columns were tested in liquid chromatography-electrospray ionization-mass spectrometry mode for the separation of a model mixture of three proteins - ribonuclease A, cytochrome c and myoglobin. Excellent repeatability of retention times was observed for the proteins as evidenced by relative standard deviation (RSD) values of less than 1.5%. Somewhat broader variations with RSD values of up to 10% were observed for the pressure drop in the columns. The stability of retention times was also monitored using a single monolithic column and no significant shifts in either retention times or back pressure was observed in a series of almost 2200 consecutive protein separations. PMID:17182044

  5. Analysis of drugs in plasma samples from schizophrenic patients by column-switching liquid chromatography-tandem mass spectrometry with organic-inorganic hybrid cyanopropyl monolithic column.

    PubMed

    Domingues, Diego Soares; Souza, Israel Donizeti de; Queiroz, Maria Eugênia Costa

    2015-07-01

    This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R(2)) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from -14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL(-1). The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM).

  6. Rapid determination of Papaver somniferum alkaloids in process streams using monolithic column high-performance liquid chromatography with chemiluminescence detection.

    PubMed

    Costin, Jason W; Lewis, Simon W; Purcell, Stuart D; Waddell, Lucy R; Francis, Paul S; Barnett, Neil W

    2007-07-30

    We have combined high-performance liquid chromatography (HPLC) separations using a monolithic column with acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection in a rapid and highly sensitive method to monitor the process of extracting opiate alkaloids from Papaver somniferum. Due to the high flow rates allowed with the monolithic column and the inherent selectivity of the chemiluminescence reactions, the four predominant alkaloids--morphine, codeine, oripavine and thebaine--were determined in less than 2 min. The results obtained with numerous process samples compared favourable with those of the standard HPLC methodology. Limits of detection were 1x10(-10) M, 5x10(-10) M, 5x10(-10) M and 1x10(-9) M, for morphine, codeine, oripavine and thebaine, respectively.

  7. Monolithic silica columns functionalized with substituted polyproline-derived chiral selectors as chiral stationary phases for high-performance liquid chromatography.

    PubMed

    Sancho, Raquel; Novell, Arnau; Svec, Frantisek; Minguillón, Cristina

    2014-10-01

    In this study, two polyproline-derived chiral selectors are bonded to monolithic silica gel columns. In spite of high chiral selector coverage, the derivatization was found to have only a slight effect on the hydrodynamics of the mobile phase through the column. The enantioseparation ability of the resulting chiral monolithic columns was evaluated with a series of structurally diverse racemic test compounds. When compared to analogous bead-based chiral stationary phases, higher enantioseparation and broader application domain were observed for monolithic columns. Moreover, the increase in flow rate produces a minor reduction of resolution, which permits to shorten analysis time. Additionally, increased loadability defines chiral polyproline derived monoliths as adequate for preparative chromatography.

  8. 3D printed titanium micro-bore columns containing polymer monoliths for reversed-phase liquid chromatography.

    PubMed

    Gupta, Vipul; Talebi, Mohammad; Deverell, Jeremy; Sandron, Sara; Nesterenko, Pavel N; Heery, Brendan; Thompson, Fletcher; Beirne, Stephen; Wallace, Gordon G; Paull, Brett

    2016-03-01

    The potential of 3D selective laser melting (SLM) technology to produce compact, temperature and pressure stable titanium alloy chromatographic columns is explored. A micro bore channel (0.9 mm I.D. × 600 mm long) was produced within a 5 × 30 × 30 mm titanium alloy (Ti-6Al-4V) cuboid, in form of a double handed spiral. A poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) (BuMA-co-EDMA) monolithic stationary phase was thermally polymerised within the channel for application in reversed-phase high-performance liquid chromatography. The prepared monolithic column was applied to the liquid chromatographic separation of intact proteins and peptides. Peak capacities of 69-76 (for 6-8 proteins respectively) were observed during isothermal separation of proteins at 44 °C which were further increased to 73-77 using a thermal step gradient with programmed temperature from 60 °C to 35 °C using an in-house built direct-contact heater/cooler platform based upon matching sized Peltier thermoelectric modules. Rapid temperature gradients were possible due to direct-contact between the planar metal column and the Peltier module, and the high thermal conductivity of the titanium column as compared to a similar stainless steel printed column. The separation of peptides released from a digestion of E.coli was also achieved in less than 35 min with ca. 40 distinguishable peaks at 210 nm. PMID:26873472

  9. Ultrafast UPLC-ESI-MS and HPLC with monolithic column for determination of principal flavor compounds in vanilla pods.

    PubMed

    Sharma, Upendra K; Sharma, Nandini; Sinha, Arun K; Kumar, Neeraj; Gupta, Ajai P

    2009-10-01

    In this study, two novel chromatographic methods based on monolithic column high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC) were developed for the ultrafast determination of principal flavor compounds namely vanillin, vanillic acid, p-hydroxybenzoic acid, and p-hydroxybenzaldehyde in ethanolic extracts of Vanilla planifolia pods. Good separation was achieved within 2.5 min using Chromolith RP18e column (100 mm x 4.6 mm) for HPLC and Acquity BEH C-18 (100 mm x 2.1 mm, 1.7 microm) column for UPLC. Both methods were compared in terms of total analysis time, mobile phase consumption, sensitivity, and validation parameters like precision, accuracy, LOD, and LOQ. Further, system suitability test data including resolution, capacity factor, theoretical plates, and tailing factor was determined for both the methods by ten replicate injections. Monolithic column based HPLC gave better results for most of the selected parameters while UPLC was found to be more eco-friendly with low mobile phase consumption and better sensitivity. Both methods may be used conveniently for the high throughput analysis of large number of samples in comparison to traditional particulate column.

  10. 3D printed titanium micro-bore columns containing polymer monoliths for reversed-phase liquid chromatography.

    PubMed

    Gupta, Vipul; Talebi, Mohammad; Deverell, Jeremy; Sandron, Sara; Nesterenko, Pavel N; Heery, Brendan; Thompson, Fletcher; Beirne, Stephen; Wallace, Gordon G; Paull, Brett

    2016-03-01

    The potential of 3D selective laser melting (SLM) technology to produce compact, temperature and pressure stable titanium alloy chromatographic columns is explored. A micro bore channel (0.9 mm I.D. × 600 mm long) was produced within a 5 × 30 × 30 mm titanium alloy (Ti-6Al-4V) cuboid, in form of a double handed spiral. A poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) (BuMA-co-EDMA) monolithic stationary phase was thermally polymerised within the channel for application in reversed-phase high-performance liquid chromatography. The prepared monolithic column was applied to the liquid chromatographic separation of intact proteins and peptides. Peak capacities of 69-76 (for 6-8 proteins respectively) were observed during isothermal separation of proteins at 44 °C which were further increased to 73-77 using a thermal step gradient with programmed temperature from 60 °C to 35 °C using an in-house built direct-contact heater/cooler platform based upon matching sized Peltier thermoelectric modules. Rapid temperature gradients were possible due to direct-contact between the planar metal column and the Peltier module, and the high thermal conductivity of the titanium column as compared to a similar stainless steel printed column. The separation of peptides released from a digestion of E.coli was also achieved in less than 35 min with ca. 40 distinguishable peaks at 210 nm.

  11. One-Pot Approach to Prepare Organo-silica Hybrid Capillary Monolithic Column with Intact Mesoporous Silica Nanoparticle as Building Block

    PubMed Central

    Liu, Shengju; Peng, Jiaxi; Liu, Zheyi; Liu, Zhongshan; Zhang, Hongyan; Wu, Ren’an

    2016-01-01

    A facile “one-pot” approach to prepare organo-silica hybrid capillary monolithic column with intact mesoporous silica nanoparticle (IMSN) as crosslinker and building block was described. An IMSN crosslinked octadecyl-silica hybrid capillary monolithic column (IMSN-C18 monolithic column) was successfully prepared, and the effects of fabrication conditions (e.g. concentration of intact mesoporous silica nanoparticle, polycondensation temperature, content of vinyltrimethoxysilane and stearyl methacrylate) on the structures of the IMSN-C18 monolithic column were studied in detail. The IMSN-C18 hybrid monolithic column possessed uniform morphology, good mechanical and pH stability (pH 1.1–11), which was applied to the separations of alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), as well as proteins. The minimum plate height of 10.5 μm (corresponding to 95000 N m−1) for butylbenzene and high reproducibility were achieved. The analysis of tryptic digest of bovine serum albumin (BSA) was carried out on the IMSN-C18 monolithic column by cLC coupled mass spectrometry (cLC-MS/MS), with the protein sequence coverage of 87.5% for BSA, demonstrating its potential application in proteomics. PMID:27698475

  12. Preparation of quaternary amine monolithic column for strong anion-exchange chromatography and its application to the separation of Enterovirus 71.

    PubMed

    Gu, Huimin; Yin, Dezhong; Ren, Jie; Zhang, Baoliang; Zhang, Qiuyu

    2016-10-15

    Large size virion is unable to diffuse into pores of conventional porous chromatography particles. Therefore, separation of virion by conventional column-packing materials is not quite efficient. To solve this problem, a monolithic column with large convective pores and quaternary amine groups was prepared and was applied to separate Enterovirus 71 (EV71, ≈5700-6000kDa). Cross-section, pore structure, hydrodynamic performance, adsorption property and dynamic binding capacity of prepared monolithic column were determined. Double-pore structures, macropore at 2472nm and mesopore at 5-60nm, were formed. The porosity was up to 63.3%, which enable higher permeability and lower back pressure of the monolithic column than commercial UNO™ Q1 column. Based on the breakthrough curves, the loading capacity of bovine serum albumin was calculated to be 42.0mg per column. In addition, prepared quaternary amine monolithic column was proved to be suitable for the separation of protein mixture by strong anion-exchange chromatography. As a practical application, prepared monolith column presents excellent performance to the separation of EV71 from virus-proteins mixture.

  13. Controlling retention, selectivity and magnitude of EOF by segmented monolithic columns consisting of octadecyl and naphthyl monolithic segments--applications to RP-CEC of both neutral and charged solutes.

    PubMed

    Karenga, Samuel; El Rassi, Ziad

    2011-04-01

    Monolithic capillaries made of two adjoining segments each filled with a different monolith were introduced for the control and manipulation of the electroosmotic flow (EOF), retention and selectivity in reversed phase-capillary electrochromatography (RP-CEC). These columns were called segmented monolithic columns (SMCs) where one segment was filled with a naphthyl methacrylate monolith (NMM) to provide hydrophobic and π-interactions, while the other segment was filled with an octadecyl acrylate monolith (ODM) to provide solely hydrophobic interaction. The ODM segment not only provided hydrophobic interactions but also functioned as the EOF accelerator segment. The average EOF of the SMC increased linearly with increasing the fractional length of the ODM segment. The neutral SMC provided a convenient way for tuning EOF, selectivity and retention in the absence of annoying electrostatic interactions and irreversible solute adsorption. The SMCs allowed the separation of a wide range of neutral solutes including polycyclic aromatic hydrocarbons (PAHs) that are difficult to separate using conventional alkyl-bonded stationary phases. In all cases, the k' of a given solute was a linear function of the fractional length of the ODM or NMM segment in the SMCs, thus facilitating the tailoring of a given SMC to solve a given separation problem. At some ODM fractional length, the fabricated SMC allowed the separation of charged solutes such as peptides and proteins that could not otherwise be achieved on a monolithic column made from NMM as an isotropic stationary phase due to the lower EOF exhibited by this monolith.

  14. Analysis of parabens in cosmetics by low pressure liquid chromatography with monolithic column and chemiluminescent detection.

    PubMed

    Ballesta Claver, J; Valencia, M C; Capitán-Vallvey, L F

    2009-07-15

    This paper presents an application of chromatographic separation based on an ultra-short monolithic column and chemiluminescent detection in an FIA type instrument manifold for the determination of four paraben mixtures: methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP). The separation is achieved in 150 s using two consecutive carriers: first 12% ACN:water that changes 75 s after injection to 27% ACN:water. The detection is based on the oxidation of the hydrolysis product of parabens, p-hydroxybenzoic acid, with Ce(IV) in the presence of Rhodamine 6G which evokes chemiluminescence of sufficient intensity to enable a sensitive determination of these species. After optimization of the variables involved, the analytical method is characterized, displaying the following values for concentration ranges, detection limits and precision, as relative standard deviation at low concentration (0.15 mg l(-1))-MP: from 9.9x10(-7) to 3.3x10(-4)M; 1.9x10(-8); 5.6%; EP: from 9.0x10(-7) to 3.3x10(-4)M; 2.8x10(-8); 3.5%; PP: from 8.3x10(-7) to 9.9x10(-5)M; 2.3x10(-8); 4.2%; and BP: from 7.7x10(-7) to 9.9x10(-5)M; 4.2x10(-8)M; 6.2%. The method was applied and validated satisfactorily for the determination of these parabens in cosmetic samples, comparing the results against a liquid chromatography reference method.

  15. Fast determination of prominent carotenoids in tomato fruits by CEC using methacrylate ester-based monolithic columns.

    PubMed

    Adalid, Ana Maria; Herrero-Martínez, José Manuel; Roselló, Salvador; Maquieira, Angel; Nuez, Fernando

    2007-11-01

    In this study, the major carotenoids (beta-carotene and lycopene) present in tomato fruits were analyzed by CEC with a methacrylate ester-based monolithic column. The effects of the porogenic solvent ratio, and the hydrophobicity of bulk monomer employed were examined on carotenoids separations. A fast separation of these analytes was achieved in less than 5.0 min in a mobile phase containing 35% THF, 30% ACN, 30% methanol, and 5% of a 5 mM Tris aqueous buffer, pH 8, with lauryl methacrylate-based monoliths. The CEC method was evaluated in terms of detection limit and reproducibility (retention time, area, and column preparation) with values below 1.6 microg/mL and 7.2%, respectively. The proposed procedure was successfully applied to the determination of both carotenoids in fruits of several tomato-related species and its usefulness to analyze large series of samples for nutritional quality screening trials in tomato breeding programs is demonstrated. To our knowledge, this is the first work that exploits the powerful and user-friendly monolithic technology for quality breeding and germplasm evaluation program purposes.

  16. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    PubMed

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes.

  17. Rigid porous polyacrylamide-based monolithic columns containing butyl methacrylate as a separation medium for the rapid hydrophobic interaction chromatography of proteins.

    PubMed

    Xie, S; Svec, F; Fréchet, J M

    1997-07-18

    Macroporous poly(acrylamide-co-butyl methacrylate-co-N,N'-methylenebisacrylamide) monoliths containing up to 15% butyl methacrylate units have been prepared by direct polymerization within the confines of HPLC columns. The hydrodynamic and chromatographic properties of these 50 mm x 8 mm I.D. columns-such as back pressure at different flow-rates, effect of percentage of hydrophobic component in the polymerization mixture, effect of salt concentration on the retention of proteins, dynamic loading capacity, and recovery-were determined under conditions typical of hydrophobic interaction chromatography. Using the monolithic column, five proteins were easily separated within only 3 min.

  18. Application of a low impedance contactless conductometric detector for the determination of inorganic cations in capillary monolithic column chromatography.

    PubMed

    Shen, Dazhong; Li, Dongdong; Yang, Xiuwen; Zhu, Yan; Dong, Jianfeng; Kang, Qi

    2011-03-15

    Poly(glycidyl methacrylate) cation exchange monolithic column was prepared in fused-silica capillaries of 320 μm i.d. by thermally initiated radical polymerization and utilized in capillary ion chromatography. With 15 mM methanesulfonic acid as the mobile phase, the separations of a mixture of inorganic cations (Li(+), Na(+), NH(4)(+), K(+)) was tested by using a capacitively coupled contactless conductivity detector (C(4)D) and a low impedance C(4)D (LIC(4)D). The LIC(4)D is the series combination of a C(4)D and a quartz crystal resonator. At the resonant frequency of the series combination, the capacitor impedance from capillary wall was offset by the inductance impedance from the quartz crystal resonator. A minimum impedance was obtained in the impedance-frequency curve of the combination. The responses of the C(4)D and LIC(4)D were analyzed based on an equivalent circuit model. It was shown that the sensitivity of the C(4)D to the change in analyte concentration is rather poor due to the high ratio of the impedance from the capillary wall capacitor to the solution impedance. The LIC(4)D has the similar sensitivity as a contact conductivity detector but a much smaller cell volume. The on-column detection model was realized by LiC(4)D without preparation of optical detection window in monolithic column.

  19. Improving permeability and chromatographic performance of poly(pentaerythritol diacrylate monostearate) monolithic column via photo-induced thiol-acrylate polymerization.

    PubMed

    Wang, Hongwei; Ou, Junjie; Bai, Jingyao; Liu, Zhongshan; Yao, Yating; Chen, Lianfang; Peng, Xiaojun; Zou, Hanfa

    2016-03-01

    A simple approach was developed for rapid preparation of polymeric monolithic columns in UV-transparent fused-silica capillaries via photoinitiated thiol-acrylate polymerization of pentaerythritol diacrylate monostearate (PEDAS) and trimethylolpropane tris(3-mercaptopropionate) (TPTM) within 10min, in which the acrylate homopolymerized and copolymerized with the thiol simultaneously. The morphology, permeability and chromatographic performance of the resulting poly(PEDAS-co-TPTM) monoliths were studied. It could be observed from SEM that the morphology of poly(PEDAS-co-TPTM) monolith was rather different from that of poly(PEDAS) monolith, which was fabricated via photo-induced free radical polymerization using PEDAS as the sole monomer. Compared with poly(PEDAS) monolith, poly(PEDAS-co-TPTM) monolith possessed better permeability when they were fabricated under the same preparation conditions. By adjusting the composition of porogenic solvents, poly(PEDAS-co-TPTM) monolith exhibited lower plate heights (15.7-17.7μm) than poly(PEDAS) monolith (19.1-37.9μm) in μLC. In addition, 66 unique peptides were positively identified on poly(PEDAS-co-TPTM) monolith when tryptic digest of four proteins was separated by μLC-MS/MS, demonstrating its potential in proteome analysis. PMID:26852266

  20. Lactoferrin Isolation Using Monolithic Column Coupled with Spectrometric or Micro-Amperometric Detector

    PubMed Central

    Adam, Vojtech; Zitka, Ondrej; Dolezal, Petr; Zeman, Ladislav; Horna, Ales; Hubalek, Jaromir; Sileny, Jan; Krizkova, Sona; Trnkova, Libuse; Kizek, Rene

    2008-01-01

    Lactoferrin is a multifunctional protein with antimicrobial activity and others to health beneficial properties. The main aim of this work was to propose easy to use technique for lactoferrin isolation from cow colostrum samples. Primarily we utilized sodium dodecyl sulphate – polyacrylamide gel electrophoresis for isolation of lactoferrin from the real samples. Moreover we tested automated microfluidic Experion electrophoresis system to isolate lactoferrin from the collostrum sample. The well developed signal of lactoferrin was determined with detection limit (3 S/N) of 20 ng/ml. In spite of the fact that Experion is faster than SDS-PAGE both separation techniques cannot be used in routine analysis. Therefore we have tested third separation technique, ion exchange chromatography, using monolithic column coupled with UV-VIS detector (LC-UV-VIS). We optimized wave length (280 nm), ionic strength of the elution solution (1.5 M NaCl) and flow rate of the retention and elution solutions (0.25 ml/min and 0.75 ml/min. respectively). Under the optimal conditions the detection limit was estimated as 0.1 μg/ml of lactoferrin measured. Using LC-UV-VIS we determined that lactoferrin concentration varied from 0.5 g/l to 1.1 g/l in cow colostrums collected in the certain time interval up to 72 hours after birth. Further we focused on miniaturization of detection device. We tested amperometric detection at carbon electrode. The results encouraged us to attempt to miniaturise whole detection system and to test it on analysis of real samples of human faeces, because lactoferrin level in faeces is closely associated with the inflammations of intestine mucous membrane. For the purpose of miniaturization we employed the technology of printed electrodes. The detection limit of lactoferrin was estimated as 10 μg/ml measured by the screen-printed electrodes fabricated by us. The fabricated electrodes were compared with commercially available ones. It follows from the obtained

  1. Oligomers matrix-assisted dispersion of high content of carbon nanotubes into monolithic column for online separation and enrichment of proteins from complex biological samples.

    PubMed

    Zhou, Chanyuan; Du, Zhuo; Li, Gongke; Zhang, Yukui; Cai, Zongwei

    2013-10-01

    In this work, a new oligomer matrix-assisted dispersion (OMAD) method for the preparation of homogeneous dispersion of multi-walled carbon nanotubes (MWNTs) incorporated monolithic column was developed. Oligomers matrix as a scaffold could allow MWNTs to entangle with it instead of self-aggregation, so the MWNTs remain in the polymer network followed by in situ self-solidification. The OMAD method not only greatly enlarged the BET surface area of MWNTs incorporated monolithic column from 13.8 m(2) g(-1) to 85.5 m(2) g(-1) without a significant effect on the surface chemistry of the MWNTs, but also improved the dispersion of MWNTs making its content up to 5 wt% (with respect to monomers). The synthesized materials combine the favorable attributes of both high permeability and large surface area, making them excellent candidates for on-line separation and enrichment of proteins. The oligomer matrix-assisted dispersion MWNTs incorporated monolithic columns (OMAD-MMC) exhibited higher enrichment factors and the adsorption capacity is about 5-fold for basic proteins compared with MWNTs incorporated monolithic columns (MMC) prepared by the conventional in situ polymerization. The practical application of OMAD-MMC was proven by selective extraction of hemoglobin in human whole blood samples with SDS-PAGE. On the basis of the results, OMAD as a simple and effective method for dispersion high content MWNTs into monolithic columns shows great promise.

  2. Oligomers matrix-assisted dispersion of high content of carbon nanotubes into monolithic column for online separation and enrichment of proteins from complex biological samples.

    PubMed

    Zhou, Chanyuan; Du, Zhuo; Li, Gongke; Zhang, Yukui; Cai, Zongwei

    2013-10-01

    In this work, a new oligomer matrix-assisted dispersion (OMAD) method for the preparation of homogeneous dispersion of multi-walled carbon nanotubes (MWNTs) incorporated monolithic column was developed. Oligomers matrix as a scaffold could allow MWNTs to entangle with it instead of self-aggregation, so the MWNTs remain in the polymer network followed by in situ self-solidification. The OMAD method not only greatly enlarged the BET surface area of MWNTs incorporated monolithic column from 13.8 m(2) g(-1) to 85.5 m(2) g(-1) without a significant effect on the surface chemistry of the MWNTs, but also improved the dispersion of MWNTs making its content up to 5 wt% (with respect to monomers). The synthesized materials combine the favorable attributes of both high permeability and large surface area, making them excellent candidates for on-line separation and enrichment of proteins. The oligomer matrix-assisted dispersion MWNTs incorporated monolithic columns (OMAD-MMC) exhibited higher enrichment factors and the adsorption capacity is about 5-fold for basic proteins compared with MWNTs incorporated monolithic columns (MMC) prepared by the conventional in situ polymerization. The practical application of OMAD-MMC was proven by selective extraction of hemoglobin in human whole blood samples with SDS-PAGE. On the basis of the results, OMAD as a simple and effective method for dispersion high content MWNTs into monolithic columns shows great promise. PMID:23917344

  3. Attapulgite Nanoparticles-Modified Monolithic Column for Hydrophilic In-Tube Solid-Phase Microextraction of Cyromazine and Melamine.

    PubMed

    Wang, Tingting; Chen, Yihui; Ma, Junfeng; Qian, Qian; Jin, Zhenfeng; Zhang, Lihua; Zhang, Yukui

    2016-02-01

    In current study, a novel monolithic capillary column with embedded attapulgite nanoparticles has been developed and exploited as a stationary phase in hydrophilic in-tube solid phase microextraction (SPME) of cyromazine and melamine. The fibrillar attapulgite nanoparticles were embedded in the poly(1-vinyl-3-(butyl-4-sulfonate) imidazolium-co-acrylamide-co-N,N'-methylenebis(acrylamide)) (poly(VBSIm-AM-MBA)) monolith via in situ polymerization. The attapulgite/polymerization ratio of the monolith was finely optimized. Primary factors of in-tube SPME including sample solvent, elution solvent, sample loading volume, elution volume, sample loading flow rate, and elution flow rate were thoroughly evaluated. Under optimal conditions, the limits of detection (LODs) were found to be 21.1 and 0.3 ng mL(-1) for cyromazine and melamine in the milk formula sample, respectively. Also, the recoveries of cyromazine and melamine spiked in the sample ranged from 94.5% to 109.9% with RSDs less than 7.6%. PMID:26743944

  4. Preparation of an aptamer based organic-inorganic hybrid monolithic column with gold nanoparticles as an intermediary for the enrichment of proteins.

    PubMed

    Zhao, Jin-Cheng; Zhu, Qing-Yun; Zhao, Ling-Yu; Lian, Hong-Zhen; Chen, Hong-Yuan

    2016-08-01

    A novel strategy for the preparation of an aptamer based organic-inorganic hybrid affinity monolithic column was developed successfully using gold nanoparticles (GNPs) as an intermediary for a sandwich structure to realize the functional modification of the surface of the monolithic matrix. This monolithic matrix was facilely pre-synthesized via one-step co-condensation. Due to the high surface-to-volume ratio of GNPs and the large specific surface area of the hybrid matrix, the average coverage density of aptamers on the hybrid monolith reached 342 pmol μL(-1). With the combination of an aptamer based hybrid affinity monolithic column and enzymatic chromogenic assay, the quantitation and detection limits of thrombin were as low as 5 nM and 2 nM, respectively. These results indicated that the GNPs attached monolith provided a novel technique to immobilize aptamers on an organic-inorganic hybrid monolith and it could be used to achieve highly selective recognition and determination of trace proteins. PMID:27307035

  5. Property evaluations and application for separation of small molecules of a nanodiamond-polymer composite monolithic column.

    PubMed

    Wang, Fengqing; Wei, Aile; Wang, Xixi; Liu, Haiyan; Bai, Ligai; Yan, Hongyuan

    2016-07-01

    A nanodiamond-polymer composite monolithic column was first prepared successfully with modified nanodiamond (ND) as monomer, ethylene glycol dimethacrylate (EDMA) as cross-linker, 1-dodecanol as porogenic agent and benzoyl peroxide/dimethylacetamide (BPO/DMA) as initiator at 35°C for 2.5h. There was a sharp increase of specific surface area with ND added about 22 times from 0mg (3.90m(2)/g) to 7mg (81.2m(2)/g) determined with BET. Characterizations including scanning electron microscopy (SEM), fourier-transform infrared spectra (FIRT) and mercury intrusion porosimetry (MIP) were used to determine the microstructure, group composition, pore size distribution (≃1.56μm) and porosity (≃0.7484μm) of the monolith. An excellent column stability was confirmed by permeability (1.258x10(-10)cm(2)) and good linearity (R(2)=0.998) corresponding to backpressures measured at different flow rates. The highest swelling ability of the composite was about (5%) and classical RPLC of the column obtained occurred with the acetonitrile concentration increasing from 20% to 85% in the mobile phase, above which another retention model of normal-phase chromatography appeared. The items of the eddy dispersion and the absorption-release kinetics were the decisional factors of the composite column compared with the factors of longitudinal diffusion, and the skeleton-eluent mass transfer resistance due to the finite diffusivity. Good separation of neutral and basic small molecules was obtained (24,350 plates/m for neutral molecules and 22,300 plates/m for basic ones) with the hydrophobicity retention mechanism, but not for the acidic ones except to regulate the pH of the mobile phase. PMID:27154670

  6. Determination of ambroxol hydrochloride, methylparaben and benzoic acid in pharmaceutical preparations based on sequential injection technique coupled with monolithic column.

    PubMed

    Satínský, Dalibor; Huclová, Jitka; Ferreira, Raquel L C; Montenegro, Maria Conceição B S M; Solich, Petr

    2006-02-13

    The porous monolithic columns show high performance at relatively low pressure. The coupling of short monoliths with sequential injection technique (SIA) results in a new approach to implementation of separation step to non-separation low-pressure method. In this contribution, a new separation method for simultaneous determination of ambroxol, methylparaben and benzoic acid was developed based on a novel reversed-phase sequential injection chromatography (SIC) technique with UV detection. A Chromolith SpeedROD RP-18e, 50-4.6 mm column with 10 mm precolumn and a FIAlab 3000 system with a six-port selection valve and 5 ml syringe were used for sequential injection chromatographic separations in our study. The mobile phase used was acetonitrile-tetrahydrofuran-0.05M acetic acid (10:10:90, v/v/v), pH 3.75 adjusted with triethylamine, flow rate 0.48 mlmin(-1), UV-detection was at 245 nm. The analysis time was <11 min. A new SIC method was validated and compared with HPLC. The method was found to be useful for the routine analysis of the active compounds ambroxol and preservatives (methylparaben or benzoic acid) in various pharmaceutical syrups and drops.

  7. Capillary electrochromatography-atmospheric pressure ionization mass spectrometry of pesticides using a surfactant-bound monolithic column

    PubMed Central

    Gu, Congying; Shamsi, Shahab A.

    2011-01-01

    A surfactant bound poly (11-acrylaminoundecanoic acid-ethylene dimethacrylate) (AAUA-EDMA) monolithic column was simply prepared by in-situ co-polymerization of AAUA and EDMA with 1-propanol, 1,4-butanediol and water as porogens in 100 µm id fused silica capillary in one step. This column was used in capillary electrochromatography (CEC)-atmospheric pressure photoionization (APPI)-mass spectrometry system for separation and detection of N-methylcarbamates (NMCs) pesticides. Numerous parameters are optimized for CEC-APPI-MS. After evaluation of the mobile phase composition, sheath liquid composition and the monolithic capillary outlet position, a fractional factorial design (FFD) was selected as a screening procedure to identify factors of ionization source parameters, such as sheath liquid flow rate, drying gas flow rate, drying gas temperature, nebulizing gas pressure, vaporizer temperature, and capillary voltage, which significantly influence APPI-MS sensitivity. A face-centered central composite design (CCD) was further utilized to optimize the most significant parameters and predict the best sensitivity. Under optimized conditions signal-to-noise ratios (S/N) around 78 were achieved for an injection of 100 ng/mL of each pesticide. Finally, this CEC-APPI-MS method was successfully applied to the analysis of nine NMCs in spiked apple juice sample after solid phase extraction with recoveries in the range of 65 to 109%. PMID:20349511

  8. Quest for organic polymer-based monolithic columns affording enhanced efficiency in high performance liquid chromatography separations of small molecules in isocratic mode.

    PubMed

    Svec, Frantisek

    2012-03-01

    The separations of small molecules using columns containing porous polymer monoliths invented two decades ago went a long way from the very modest beginnings to the current capillary columns with efficiencies approaching those featured by their silica-based counterparts. This review article presents a variety of techniques that have been used to form capillary formats of monolithic columns with enhanced separation performance in isocratic elutions. The following text first describes the traditional approaches used for the preparation of efficient monoliths comprising variations in polymerization conditions including temperature as well as composition of monomers and porogenic solvents. Encouraging results of these experiments fueled research of completely new preparation methods such as polymerization to an incomplete conversion, use of single crosslinker, hypercrosslinking, and incorporation of carbon nanotubes that are described in the second part of the text. PMID:21816401

  9. Polyacrylamide-based monolithic capillary column with coating of cellulose tris(3,5-dimethylphenyl-carbamate) for enantiomer separation in capillary electrochromatography.

    PubMed

    Dong, Xiaoli; Wu, Ren'an; Dong, Jing; Wu, Minghuo; Zhu, Yan; Zou, Hanfa

    2008-02-01

    A hydrophilic chiral capillary monolithic column for enantiomer separation in CEC was prepared by coating cellulose tris(3,5-dimethylphenyl-carbamate) (CDMPC) on porous hydrophilic poly(acrylamide-co-N,N'-methylene-bisacrylamide) (poly(AA-co-MBA)) monolithic matrix with confine of a fused-silica capillary. The coating conditions were optimized to obtain a stable and reproducible chiral stationary phase for CEC. The effect of organic modifier of ACN in aqueous mobile phase for the enantiomer separation by CEC was investigated, and the significant influence of ACN on the enantioresolution and electrochromatographic retention was observed. Twelve pairs of enantiomers including acidic, neutral, and basic analytes were tested and nine pairs of them were baseline-enantioresolved with acidic and basic aqueous mobile phases. A good within-column repeatability in retention time (RSD = 2.4%) and resolution (RSD = 3.2%) was obtained by consecutive injections of a neutral compound, benzoin, on a prepared chiral monolithic column, while the between-column repeatability in retention time (RSD = 6.4%) and resolution (RSD = 9.6%) was observed by column-to-column examination. The prepared monolithic stationary phase showed good stability in either acidic or basic mobile phase.

  10. Polyacrylamide-based monolithic capillary column with coating of cellulose tris(3,5-dimethylphenyl-carbamate) for enantiomer separation in capillary electrochromatography.

    PubMed

    Dong, Xiaoli; Wu, Ren'an; Dong, Jing; Wu, Minghuo; Zhu, Yan; Zou, Hanfa

    2008-02-01

    A hydrophilic chiral capillary monolithic column for enantiomer separation in CEC was prepared by coating cellulose tris(3,5-dimethylphenyl-carbamate) (CDMPC) on porous hydrophilic poly(acrylamide-co-N,N'-methylene-bisacrylamide) (poly(AA-co-MBA)) monolithic matrix with confine of a fused-silica capillary. The coating conditions were optimized to obtain a stable and reproducible chiral stationary phase for CEC. The effect of organic modifier of ACN in aqueous mobile phase for the enantiomer separation by CEC was investigated, and the significant influence of ACN on the enantioresolution and electrochromatographic retention was observed. Twelve pairs of enantiomers including acidic, neutral, and basic analytes were tested and nine pairs of them were baseline-enantioresolved with acidic and basic aqueous mobile phases. A good within-column repeatability in retention time (RSD = 2.4%) and resolution (RSD = 3.2%) was obtained by consecutive injections of a neutral compound, benzoin, on a prepared chiral monolithic column, while the between-column repeatability in retention time (RSD = 6.4%) and resolution (RSD = 9.6%) was observed by column-to-column examination. The prepared monolithic stationary phase showed good stability in either acidic or basic mobile phase. PMID:18219649

  11. Quantification of malachite green in fish feed utilising liquid chromatography-tandem mass spectrometry with a monolithic column.

    PubMed

    Abro, Kamran; Mahesar, Sarfaraz Ahmed; Iqbal, Seema; Perveen, Shahnaz

    2014-01-01

    The purpose of this study was to develop a rapid and sensitive method for the quantification of malachite green (MG) in fish feed using LC-ESI-MS/MS with a monolithic column as stationary phase. Fish feed was cleaned using ultrasonic assisted liquid-liquid extraction. The separation was achieved on a Chromolith® Performance RP-18e column (100 × 4.6 mm) using gradient mobile phase composition of methanol and 0.1% formic acid at the flow rate of 1.0 ml min⁻¹. The analyte was ionised using electrospray ionisation in positive mode. Mass spectral transitions were recorded in selected reaction monitoring (SRM) mode at m/z 329.78 → m/z 314.75 with a collision energy (CE) of 52% for MG. The system suitability responses were calculated for reproducibility tests of the retention time, number of theoretical plates and capacity factor. System validation was evaluated for precision, specificity and linearity of MG. The linearity and calibration graph was plotted in the range of 15.0-250 ng ml⁻¹ with the regression coefficient of >0.997. The lower limits of detection and quantification for MG were 0.55 and 1.44 ng ml⁻¹, respectively, allowing easy determination in fish feed with accuracy evaluated as a percentage recovery of 92.1% and precision determined as % CV of < 5. The method was also extended to the determination of MG in an actual fish feed. The sensitivity and selectivity of LC-ESI-MS/MS using monolithic column offers a valuable alternative to the methodologies currently employed for the quantification of MG in fish feeds.

  12. Rapid separation and highly sensitive detection methodology for sulfonamides in shrimp using a monolithic column coupled with BDD amperometric detection.

    PubMed

    Sangjarusvichai, Haruthai; Dungchai, Wijitar; Siangproh, Weena; Chailapakul, Orawon

    2009-09-15

    In this report, we aimed to extend our previous efforts toward the evaluation of sulfonamides (SAs) with a boron-doped diamond (BDD) electrode. We improved this method by reducing the analysis time using a monolithic column coupled with amperometric detection to determine seven sulfonamides (sulfaguanidine, sulfadiazine, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline). Because of its rapid separation, low back-pressure and high separation efficiency compared to a particle-packed column, a monolithic column (100 mm x 4.6mm) was used for sulfonamide separation. Chromatographic separation was performed in less than 8 min. The analysis was carried out using phosphate buffer (0.1M, pH 3): acetonitrile: methanol in a ratio of 80:15:5 (v/v/v) as the mobile phase with a flow rate of 1.5 mL min(-1). The optimal detection potential using hydrodynamic voltammetry was found to be 1.2V versus Ag/AgCl. The method was applied to determine seven sulfonamides in shrimp after sample preparation by solid-phase extraction. The recoveries of the sulfonamides in spiked shrimp samples at 1.5, 5 and 10 microg g(-1) were in the range of 81.7 to 97.5% with a relative standard deviation (R.S.D.) between 1.0 and 4.6%. Our methodology produced results that were highly correlated with HPLC-MS data. Therefore, we propose a method that can be used for the rapid, selective and sensitive evaluation of sulfonamides in contaminated food. PMID:19615505

  13. Histidine-modified organic-silica hybrid monolithic column for mixed-mode per aqueous and ion-exchange capillary electrochromatography.

    PubMed

    Tang, Sheng; Liu, Shujuan; Liang, Xiaojing; Tang, Xiaofen; Wu, Xingcai; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2015-06-01

    A novel organic-silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed-mode per aqueous and ion-exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro-osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water-rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed-mode mechanism of hydrophobic and ion-exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine-modified organic-silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds.

  14. Preparation of porous polymer monolithic column using functionalized graphene oxide as a functional crosslinker for high performance liquid chromatography separation of small molecules.

    PubMed

    Li, Yaping; Qi, Li; Ma, Huimin

    2013-09-21

    A newly developed porous polymer monolith was prepared through copolymerization of 3-(trimethoxysilyl)propylmethacrylate modified graphene oxide with glycidyl methacrylate and ethylene dimethacrylate as a functional crosslinker, which was synthesized through silanization reaction of graphene oxide prepared by Hummers method with 3-(trimethoxysilyl)propylmethacrylate. The monolith was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, mercury intrusion porosimetry and nitrogen adsorption measurement. The monolith column was applied as the stationary phase of high performance liquid chromatography and its chromatographic performance was evaluated by separation of small molecules in the isocratic reversed-phase mode. The chromatograms of hydrophobic steroids and polar aromatic amines on the prepared monolith displayed the enhanced separation performance over those on the parent monolith. The reproducibility of the column was less than 3.5% in terms of relative standard deviation of retention time. The results demonstrate that copolymerization of functionalized graphene oxide into porous polymer monolith was an effective tool for chromatography separation enhancement of small molecules in an isocratic mode. PMID:23884304

  15. Simple and fast analysis of iohexol in human serums using micro-hydrophilic interaction liquid chromatography with monolithic column.

    PubMed

    Chaloemsuwiwattanakan, Thotsaphorn; Sangcakul, Areeporn; Kitiyakara, Chagriya; Nacapricha, Duangjai; Wilairat, Prapin; Chaisuwan, Patcharin

    2016-09-01

    A simple and rapid method based on micro-liquid chromatography using a synthetic monolithic capillary column was developed for determination of iohexol in human serums, a marker to evaluate the glomerular filtration rate. A hydrophilic methacrylic acid-ethylene dimethacrylate monolith provided excellent selectivity and efficiency for iohexol with separation time of 3 min using a mobile phase of 40:60 v/v 50 mM phosphate buffer pH 5/methanol. Four serum protein removal, methods using perchloric acid, 50% acetonitrile, 0.1 M zinc sulfate, and centrifuge membrane filter were examined. The method of zinc sulfate was chosen due to its simplicity, compatibility with the mobile phase system, nontoxicity, and low cost. Interday calibration curves were conducted over iohexol concentrations range of 2-500 mg/L (R(2) = 0.9997 ± 0.0001) with detection limit of 0.44 mg/L. Intra- and interday precisions for peak area and retention time were less than 2.8 and 1.4%, respectively. The method was successfully applied to serum samples with percent recoveries from 102 to 104. The method was applied to monitor released iohexol from healthy subject. Compared with the commercially available reversed-phase high-performance liquid chromatography method, the presented method provided simpler chromatogram, faster separation with higher separation efficiency and much lower sample and solvent consumption. PMID:27443792

  16. LC-determination of five paraben preservatives in saliva and toothpaste samples using UV detection and a short monolithic column.

    PubMed

    Zotou, Anastasia; Sakla, Ioanna; Tzanavaras, Paraskevas D

    2010-11-01

    The present study reports the development and application of an HPLC-UV method for the simultaneous separation and determination of five paraben preservatives (methyl-, ethyl-, propyl-, n-butyl- and iso-butyl-paraben) in real samples. All analytes were separated efficiently in less than 20 min using a simple H(2)O:ACN linear gradient and a short monolithic column (50 mm x 4.6mm i.d.) at a flow rate of 3.0mL min(-1). Phenoxyethanol was used as chromatographic internal standard. The method was validated for linearity, limits of detection and quantification, accuracy and precision. Human saliva and toothpaste samples were analyzed after SPE pretreatment on Licrolut RP-18 cartridges. The detection limits varied between 0.1 and 0.3 mg L(-1) in all cases and the percent recoveries between 86 and 113%.

  17. Monolithic poly(N-vinylcarbazole-co-1,4-divinylbenzene) capillary columns for the separation of biomolecules.

    PubMed

    Koeck, Rainer; Bakry, Rania; Tessadri, Richard; Bonn, Guenther K

    2013-09-01

    Monolithic capillary columns were prepared by thermally initiated free radical copolymerization of N-vinylcarbazole (NVC) and 1,4-divinylbenzene (DVB) within the confines of 200 and 100 μm i.d. fused silica capillaries. The reaction was carried out under the influence of inert micro-(toluene) and macroporogen (1-decanol) and α,α'-azoisobutyronitrile (AIBN) as a free radical initiator. The material proved high mechanical stability applying water and acetonitrile as mobile phases. The morphological and porous properties were studied by scanning electron microscopy (SEM), nitrogen sorption (BET) and mercury intrusion porosimetry (MIP). The homogeneity of the copolymerization process was confirmed by elemental analysis and monomer conversion measurements. The newly developed NVC/DVB monolithic supports showed high separation efficiency towards biomolecules, applying reversed-phase (RP) and ion-pair reversed-phase (IP-RP) separation modes, which is exemplified by the separations of peptides, proteins and oligonucleotides. Furthermore the maximum loading capacity was evaluated. The chromatographic performance under isocratic elution was determined in terms of theoretical plate number and plate height, where up to 41,000 plates per column and a minimum plate height value of 1.7 μm were achieved, applying oligonucleotide separations. In gradient elution mode, peak capacities of 96 and 127 were achieved within a gradient time window of 60 min for protein and oligonucleotide separations, respectively. The material proved to have high permeability, good repeatability of the fabrication process and high surface areas in the range of 120-160 m(2) g(-1). PMID:23799449

  18. Online micro-solid-phase extraction based on boronate affinity monolithic column coupled with high-performance liquid chromatography for the determination of monoamine neurotransmitters in human urine.

    PubMed

    Yang, Xiaoting; Hu, Yufei; Li, Gongke

    2014-05-16

    Quantification of monoamine neurotransmitters is very important in diagnosing and monitoring of patients with neurological disorders. We developed an online analytical method to selectively determine urinary monoamine neurotransmitters, which coupled the boronate affinity monolithic column micro-solid-phase extraction with high-performance liquid chromatography (HPLC). The boronate affinity monolithic column was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and N,N'-methylenebisacrylamide (MBAA) in a stainless capillary column. The prepared monolithic column showed good permeability, high extraction selectivity and capacity. The column-to-column reproducibility was satisfactory and the enrichment factors were 17-243 for four monoamine neurotransmitters. Parameters that influence the online extraction efficiency, including pH of sample solution, flow rate of extraction and desorption, extraction volume and desorption volume were investigated. Under the optimized conditions, the developed method exhibited low limit of detection (0.06-0.80μg/L), good linearity (with R(2) between 0.9979 and 0.9993). The recoveries in urine samples were 81.0-105.5% for four monoamine neurotransmitters with intra- and inter-day RSDs of 2.1-8.2% and 3.7-10.6%, respectively. The online analytical method was sensitive, accurate, selective, reliable and applicable to analysis of trace monoamine neurotransmitters in human urine sample.

  19. Depletion of human serum albumin in embryo culture media for in vitro fertilization using monolithic columns with immobilized antibodies.

    PubMed

    Tarasova, Irina A; Lobas, Anna A; Černigoj, Urh; Solovyeva, Elizaveta M; Mahlberg, Barbara; Ivanov, Mark V; Panić-Janković, Tanja; Nagy, Zoltan; Pridatchenko, Marina L; Pungor, Andras; Nemec, Blaž; Vidic, Urška; Gašperšič, Jernej; Krajnc, Nika Lendero; Vidič, Jana; Gorshkov, Mikhail V; Mitulović, Goran

    2016-09-01

    Affinity depletion of abundant proteins such as HSA is an important stage in routine sample preparation prior to MS/MS analysis of biological samples with high range of concentrations. Due to the charge competition effects in electrospray ion source that results in discrimination of the low-abundance species, as well as limited dynamic range of MS/MS, restricted typically by three orders of magnitude, the identification of low-abundance proteins becomes a challenge unless the sample is depleted from high-concentration compounds. This dictates a need for developing efficient separation technologies allowing fast and automated protein depletion. In this study, we performed evaluation of a novel immunoaffinity-based Convective Interaction Media analytical columns (CIMac) depletion column with specificity to HSA (CIMac-αHSA). Because of the convective flow-through channels, the polymethacrylate CIMac monoliths afford flow rate independent binding capacity and resolution that results in relatively short analysis time compared with traditional chromatographic supports. Seppro IgY14 depletion kit was used as a benchmark to control the results of depletion. Bottom-up proteomic approach followed by label-free quantitation using normalized spectral indexes were employed for protein quantification in G1/G2 and cleavage/blastocyst in vitro fertilization culture media widely utilized in clinics for embryo growth in vitro. The results revealed approximately equal HSA level of 100 ± 25% in albumin-enriched fractions relative to the nondepleted samples for both CIMac-αHSA column and Seppro kit. In the albumin-free fractions concentrated 5.5-fold by volume, serum albumin was identified at the levels of 5-30% and 20-30% for the CIMac-αHSA and Seppro IgY14 spin columns, respectively. PMID:27122488

  20. Depletion of human serum albumin in embryo culture media for in vitro fertilization using monolithic columns with immobilized antibodies.

    PubMed

    Tarasova, Irina A; Lobas, Anna A; Černigoj, Urh; Solovyeva, Elizaveta M; Mahlberg, Barbara; Ivanov, Mark V; Panić-Janković, Tanja; Nagy, Zoltan; Pridatchenko, Marina L; Pungor, Andras; Nemec, Blaž; Vidic, Urška; Gašperšič, Jernej; Krajnc, Nika Lendero; Vidič, Jana; Gorshkov, Mikhail V; Mitulović, Goran

    2016-09-01

    Affinity depletion of abundant proteins such as HSA is an important stage in routine sample preparation prior to MS/MS analysis of biological samples with high range of concentrations. Due to the charge competition effects in electrospray ion source that results in discrimination of the low-abundance species, as well as limited dynamic range of MS/MS, restricted typically by three orders of magnitude, the identification of low-abundance proteins becomes a challenge unless the sample is depleted from high-concentration compounds. This dictates a need for developing efficient separation technologies allowing fast and automated protein depletion. In this study, we performed evaluation of a novel immunoaffinity-based Convective Interaction Media analytical columns (CIMac) depletion column with specificity to HSA (CIMac-αHSA). Because of the convective flow-through channels, the polymethacrylate CIMac monoliths afford flow rate independent binding capacity and resolution that results in relatively short analysis time compared with traditional chromatographic supports. Seppro IgY14 depletion kit was used as a benchmark to control the results of depletion. Bottom-up proteomic approach followed by label-free quantitation using normalized spectral indexes were employed for protein quantification in G1/G2 and cleavage/blastocyst in vitro fertilization culture media widely utilized in clinics for embryo growth in vitro. The results revealed approximately equal HSA level of 100 ± 25% in albumin-enriched fractions relative to the nondepleted samples for both CIMac-αHSA column and Seppro kit. In the albumin-free fractions concentrated 5.5-fold by volume, serum albumin was identified at the levels of 5-30% and 20-30% for the CIMac-αHSA and Seppro IgY14 spin columns, respectively.

  1. Silica-based monolithic column with evaporative light scattering detector for HPLC analysis of bacosides and apigenin in Bacopa monnieri.

    PubMed

    Bhandari, Pamita; Kumar, Neeraj; Singh, Bikram; Singh, Virendra; Kaur, Inderjeet

    2009-08-01

    A high performance liquid chromatographic method using a silica-based monolithic column coupled with evaporative light scattering detector (HPLC-ELSD) was developed and validated for simultaneous quantification of bacosides (bacoside A, bacopaside I, bacoside A(3), bacopaside II, bacopaside X, bacopasaponin C) and apigenin in Bacopa monnieri. The chromatographic resolution was achieved on a Chromolith RP-18 (100x4.6 mm) column with acetonitrile/water (30:70) as mobile phase in isocratic elution at a flow rate of 0.7 mL/min. The drift tube temperature of the ELSD was set to 95 degrees C, and the nitrogen flow rate was 2.0 SLM (standard liter per minute). The calibration curves revealed a good linear relationship (r(2) > 0.9988) within the test ranges. The detection limits (S/N = 3) and the quantification limits (S/N = 10) for the compounds were in the range of 0.54-6.06 and 1.61-18.78 microg/mL, respectively. Satisfactory average recovery was observed in the range of 95.8-99.0%. The method showed good reproducibility for the quantification of these compounds in B. monnieri with intra- and inter-day precision of less than 0.69 and 0.67%, respectively. The validated method was successfully applied to quantify analytes in nine accessions of B. monnieri and thus provides a new basis for overall quality assessment of B. monnieri.

  2. Preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) monolithic column by in situ polymerization and a click reaction for capillary liquid chromatography of small molecules and proteins.

    PubMed

    Lin, Zian; Yu, Ruifang; Hu, Wenli; Zheng, Jiangnan; Tong, Ping; Zhao, Hongzhi; Cai, Zongwei

    2015-07-01

    Combining free radical polymerization with click chemistry via a copper-mediated azide/alkyne cycloaddition (CuAAC) reaction in a "one-pot" process, a facile approach was developed for the preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) (AZT-co-PMA-co-PETA) monolithic column. The resulting poly(AZT-co-PMA-co-PETA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of a monolithic column. A series of alkylbenzenes, amides, anilines, and benzoic acids were used to evaluate the chromatographic properties of the polymer monolith in terms of hydrophobic, hydrophilic and cation-exchange interactions, and the results showed that the poly(AZT-co-PMA-co-PETA) monolith exhibited more flexible adjustment in chromatographic selectivity than that of the parent poly(PMA-co-PETA) and AZT-modified poly(PMA-co-PETA) monoliths. Column efficiencies for toluene, DMF, and formamide with 35,000-48,000 theoretical plates per m could be obtained at a linear velocity of 0.17 mm s(-1). The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention factors were less than 4.2%. In addition, the proposed monolith was also applied to efficient separation of sulfonamides, nucleobases and nucleosides, anesthetics and proteins for demonstrating its potential.

  3. Capillary electrochromatography with polyacrylamide monolithic stationary phases having bonded dodecyl ligands and sulfonic acid groups: evaluation of column performance with alkyl phenyl ketones and neutral moderately polar pesticides.

    PubMed

    Zhang, M; El Rassi, Z

    2001-08-01

    In this report, we describe the preparation of porous polyacrylamide-based monolithic columns via vinyl polymerization. These monoliths possess in their structures bonded dodecyl ligands and sulfonic acid groups. While the sulfonic acid groups are meant to support the electroosmotic flow (EOF) necessary for moving the mobile phase through the monolithic capillary, the dodecyl ligands are introduced to provide the nonpolar sites for chromatographic retention. However, incorporating the sulfonic acid groups in the monoliths does not only support the EOF but also exhibit hydrophilic interaction with moderately polar compounds such as urea herbicides and carbamates insecticides. Consequently, mixed-mode (reversed-phase/normal phase) retention behavior is observed with neutral and moderately polar pesticides. The amount of sulfonic acid group in the monolith can be conveniently adjusted by changing the amount of vinylsulfonic acid added to the polymerization reaction. Optimum EOF velocity and adequate chromatographic retention are obtained when 15% vinylsulfonic acid is added to the reaction mixture. Under these conditions, rapid separation and high plate counts reaching greater than 400000 plates/m are readily obtained.

  4. Preparation of poly(butyl methacrylate-co-ethyleneglyceldimethacrylate) monolithic column modified with β-cyclodextrin and nano-cuprous oxide and its application in polymer monolithic microextraction of polychlorinated biphenyls.

    PubMed

    Zheng, Haijiao; Liu, Qingwen; Jia, Qiong

    2014-05-23

    A poly(butyl methacrylate-co-ethyleneglyceldimethacrylate) (poly(BMA-EDMA)) monolithic column was prepared with in situ polymerization method and modified with allylamine-β-cyclodextrin (ALA-β-CD) and nano-cuprous oxide (Cu2O). A polymer monolith microextraction method was developed with the modified monolithic column for the preconcentration of polychlorinated biphenyls combined with gas chromatography-electron capture detector. Various parameters affecting the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, we obtained acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations. Because of the hydrophobic properties of β-CD and the porous nano structure of Cu2O, the enrichment capacity of the poly(BMA-EDMA) monolithic column was significantly improved. The extraction efficiency followed the order: poly(BMA-EDMA-ALA-β-CD-Cu2O)>poly(BMA-EDMA-ALA-β-CD)>poly(BMA-EDMA)>direct GC analysis. When applied to the determination of polychlorinated biphenyls in wine samples, low limits of detection (0.09ngmL(-1)) were obtained under the preoptimized conditions (sample volume 1.0mL, sample flow rate 0.1mLmin(-1), eluent volume 0.1mL, and eluent flow rate 0.05mLmin(-1)). In addition, the present method was employed to determine polychlorinated biphenyls in red wine samples and the accuracy was assessed through recovery experiments. The obtained recovery values were in the range of 78.8-104.1% with relative standard deviations less than 9.0%. PMID:24745841

  5. Ion chromatographic determination of hydroxide ion on monolithic reversed-phase silica gel columns coated with nonionic and cationic surfactants.

    PubMed

    Xu, Qun; Mori, Masanobu; Tanaka, Kazuhiko; Ikedo, Mikaru; Hu, Wenzhi; Haddad, Paul R

    2004-07-01

    The determination of hydroxide by ion chromatography (IC) is demonstrated using a monolithic octadecylsilyl (ODS)-silica gel column coated first with a nonionic surfactant (polyoxyethylene (POE)) and then with a cationic surfactant (cetyltrimethylammonium bromide (CTAB)). This stationary phase, when used in conjunction with a 10 mmol/l sodium sulfate eluent at pH 8.2, was found to be suitable for the rapid and efficient separation of hydroxide from some other anions, based on a conventional ion-exchange mechanism. The peak directions and detection responses for these ions were in agreement with their known limiting equivalent ionic conductance values. Under these conditions, a linear calibration plot was obtained for hydroxide ion over the range 16 micromol/l to 15 mmol/l, and the detection limit determined at a signal-to-noise ratio of 3 was 6.4 micromol/l. The double-coated stationary phase described above was shown to be superior to a single coating of cetyltrimethylammonium bromide alone, in terms of separation efficiency and stability of the stationary phase. A range of samples comprising solutions of some strong and weak bases was analyzed by the proposed method and the results obtained were in good agreement with those obtained by conventional potentiometric pH measurement.

  6. Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column.

    PubMed

    Rahim, A A; Nofrizal, S; Saad, Bahruddin

    2014-03-15

    A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4 mL min(-1), the catechins and caffeine were isocratically separated in about 7 min. The limits of detection and quantification were in the range of 0.11-0.29 and 0.33-0.87 mg L(-1), respectively. Satisfactory recoveries were obtained (94.2-105.2 ± 1.8%) for all samples when spiked at three concentrations (5, 40 and 70 mg L(-1)). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas.

  7. Enantioseparation of N-derivatized amino acids by micro-liquid chromatography/laser induced fluorescence detection using quinidine-based monolithic columns.

    PubMed

    Wu, Huihui; Wang, Qiqin; Ruan, Meng; Peng, Kun; Zhu, Peijie; Crommen, Jacques; Han, Hai; Jiang, Zhengjin

    2016-03-20

    A novel carbamoylated quinidine based monolith, namely poly(O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-co-ethylene dimethacrylate (poly(MQD-co-EDMA)), was prepared for the micro-LC enantioseparation of N-derivatized amino acids. The influence of the mobile phase composition, including the organic modifier proportion, the apparent pH and the buffer concentration, on the enantioresolution of N-derivatized amino acids was systematically investigated. Satisfactory column performance in terms of permeability, efficiency and reproducibility was obtained in most cases. The majority of the enantiomers of the tested N-protected amino acids, including 3,5-DNB, 3,5-DClB, FMOC, 3,5-DMB, p-NB, m-ClB, p-ClB and B derivatives, could be baseline separated on the poly(MQD-co-EDMA) monolithic column within 25min. A self-assembled laser induced fluorescence (LIF) detector was employed to improve sensitivity when analyzing 7-nitro-2,1,3-benzoxadiazole (NBD) derivatives of amino acids. Ten NBD-derivatized amino acids, including arginine and histidine whose enantioseparation on quinidine carbamate based CSPs has not been reported so far, were enantioresolved on the poly(MQD-co-EDMA) monolith column. It is worth noting that the d-enantiomers of NBD-derivatized amino acids eluted first, except in the case of glutamic acid. The LOD values obtained with the LIF detector were comparable to those reported using conventional LC-FL methods. The prepared poly(MQD-co-EDMA) monolithic column coupled with the LIF detector opens up interesting perspectives to the determination of trace D-amino acids in biological samples. PMID:26732881

  8. Enantioseparation of N-derivatized amino acids by micro-liquid chromatography/laser induced fluorescence detection using quinidine-based monolithic columns.

    PubMed

    Wu, Huihui; Wang, Qiqin; Ruan, Meng; Peng, Kun; Zhu, Peijie; Crommen, Jacques; Han, Hai; Jiang, Zhengjin

    2016-03-20

    A novel carbamoylated quinidine based monolith, namely poly(O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-co-ethylene dimethacrylate (poly(MQD-co-EDMA)), was prepared for the micro-LC enantioseparation of N-derivatized amino acids. The influence of the mobile phase composition, including the organic modifier proportion, the apparent pH and the buffer concentration, on the enantioresolution of N-derivatized amino acids was systematically investigated. Satisfactory column performance in terms of permeability, efficiency and reproducibility was obtained in most cases. The majority of the enantiomers of the tested N-protected amino acids, including 3,5-DNB, 3,5-DClB, FMOC, 3,5-DMB, p-NB, m-ClB, p-ClB and B derivatives, could be baseline separated on the poly(MQD-co-EDMA) monolithic column within 25min. A self-assembled laser induced fluorescence (LIF) detector was employed to improve sensitivity when analyzing 7-nitro-2,1,3-benzoxadiazole (NBD) derivatives of amino acids. Ten NBD-derivatized amino acids, including arginine and histidine whose enantioseparation on quinidine carbamate based CSPs has not been reported so far, were enantioresolved on the poly(MQD-co-EDMA) monolith column. It is worth noting that the d-enantiomers of NBD-derivatized amino acids eluted first, except in the case of glutamic acid. The LOD values obtained with the LIF detector were comparable to those reported using conventional LC-FL methods. The prepared poly(MQD-co-EDMA) monolithic column coupled with the LIF detector opens up interesting perspectives to the determination of trace D-amino acids in biological samples.

  9. One-pot preparation of a mixed-mode organic-silica hybrid monolithic capillary column and its application in determination of endogenous gibberellins in plant tissues.

    PubMed

    Zhang, Zheng; Hao, Yan-Hong; Ding, Jun; Xu, Sheng-Nan; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-10-16

    A newly improved one-pot method, based on "thiol-ene" click chemistry and sol-gel approach in microemulsion system, was developed for the preparation of C8/PO(OH)2-silica hybrid monolithic capillary column. The prepared monolith possesses large specific surface area, narrow mesopore size distribution and high column efficiency. The monolithic column was demonstrated to have cation exchange/reversed-phase (CX/RP) mixed-mode retention for analytes on nano-liquid chromatography (nano-LC). On the basis of the developed nano-LC system with MS detector coupled to pipette tip solid phase extraction (PT-SPE) and derivatization process, we then realized simultaneous determination of 10 gibberellins (GAs) with low limits of detection (LODs, 0.003-0.025 ng/mL). Furthermore, 6 endogenous GAs in only 5mg rice leaves (fresh weight) were successfully detected and quantified. The developed PT-SPE-nano-LC-MS strategy may offer promising applications in the determination of low abundant bioactive molecules from complex matrix.

  10. Method development validation for corticoids in animal feed samples by liquid chromatography using a monolithic column.

    PubMed

    Muñiz-Valencia, Roberto; Gonzalo-Lumbreras, Raquel; Santos-Montes, Ana; Izquierdo-Hornillos, Roberto

    2007-11-01

    A LC method for corticosteroids (CC) determination in poultry feed using a Chromolith column and UV detection has been developed and validated. The method development involved the optimization of different hydro-organic mobile phases using methanol or ACN as organic modifiers, flow rate, and temperature. The optimum separation was achieved at 40 degrees C using ACN/water (21:79 v/v) as mobile phase and 3 mL/min flow rate, allowing the separation to baseline of four out of seven CC in about 10 min. Prior to LC, a sample preparation procedure previously assayed for anabolics was used. It includes a leaching process, saponification of the esters from fatty acids, and SPE. Method validation was carried out according to the EU criteria established for quantitative screening methods. The extraction efficiencies, decision limits (CCalpha), and detection capabilities (CCbeta) for these compounds were in the ranges of 86-92%, 27-36 microg/kg, and 33-43 microg/kg, respectively. The repeatability and the within-laboratory reproducibility at 1, 1.5, and 2 CCbeta concentration levels were smaller than 9.0, 5.0, and 4.2% and 9.4, 6.4, and 4.9%, respectively. The CV values of the robustness test were less than 3.8% and the accuracy was in the range of 98-103%. The proposed method was applied to other feed with satisfactory results.

  11. Separation of intact proteins on γ-ray-induced polymethacrylate monolithic columns: A highly permeable stationary phase with high peak capacity for capillary high-performance liquid chromatography with high-resolution mass spectrometry.

    PubMed

    Simone, Patrizia; Pierri, Giuseppe; Foglia, Patrizia; Gasparrini, Francesca; Mazzoccanti, Giulia; Capriotti, Anna Laura; Ursini, Ornella; Ciogli, Alessia; Laganà, Aldo

    2016-01-01

    Polymethacrylate-based monolithic capillary columns, prepared by γ-radiation-induced polymerization, were used to optimize the experimental conditions (nature of the organic modifiers, the content of trifluoroacetic acid and the column temperature) in the separation of nine standard proteins with different hydrophobicities and a wide range of molecular weights. Because of the excellent permeability of the monolithic columns, an ion-pair reversed-phase capillary liquid chromatography with high-resolution mass spectrometry method has been developed by coupling the column directly to the mass spectrometer without a flow-split and using a standard electrospray interface. Additionally, the high working flow and concomitant high efficiency of these columns allowed us to employ a longer column (up to 50 cm) and achieve a peak capacity value superior to 1000. This work is motivated by the need to develop new materials for high-resolution chromatographic separation that combine chemical stability at elevated temperatures (up to 75°C) and a broad pH range, with a high peak capacity value. The advantage of the γ-ray-induced monolithic column lies in the batch-to-batch reproducibility and long-term high-temperature stability. Their proven high loading capacity, recovery, good selectivity and high permeability, moreover, compared well with that of a commercially available poly(styrene-divinylbenzene) monolithic column, which confirms that such monolithic supports might facilitate analysis in proteomics.

  12. Selection of two reliable parameters to evaluate the impact of the mobile-phase composition on capillary electrochromatography performance with monolithic and particle-packed capillary columns.

    PubMed

    Progent, Frédéric; Augustin, Violaine; Tran, N Thuy; Descroix, Stéphanie; Taverna, Myriam

    2006-02-01

    Different models have been described in the literature to evaluate the total porosity of CEC columns: gravimetric, flow as well as conductivity-based methods. In this study, these models have been compared for two kinds of CEC columns: two mixed-mode silica particle stationary phases and different monolithic columns (acrylate or polystyrene divinylbenzene-based). The total porosities measured from the conductivity-based methods were lower than the total column porosities obtained by gravimetric or flow methods for all the investigated columns while the wide distribution of observed values shows that conductivity-based methods discriminate columns more efficiently with very different properties. We propose a conductivity-based method taking into account the actual length proposed by Horvath, to evaluate what we call an "actual electrokinetic" porosity (AEP). This parameter, based on electrokinetic theory only, affords the most consistent evaluation of porosity under experimental CEC conditions for the packed- and acrylate-based monolithic columns. To illustrate the potential of AEP and actual EOF for the estimation of the performances of a CEC system (stationary and mobile phases) we studied the influence of the mobile-phase composition on these parameters for CEC separations with an ammonium embedded packed stationary phase. The AEP and the actual electroosmotic mobility should allow a better understanding of the perfusive EOF and stationary-phase wettability. For neutral compounds (substituted phenols), AEP evaluation allowed us to predict the mobile-phase conditions able to enhance the efficiency while both AEP and actual EOF had to be considered in the case of peptide analysis.

  13. [Synthesis and chromatographic evaluation of sulfobetaine-based capillary zwitterionic hydrophilic monolithic column using a binary porogenic agent of polyethylene glycol/methanol].

    PubMed

    Kuang, Yuanyuan

    2014-04-01

    Sulfobetaine-based capillary zwitterionic hydrophilic monolithic columns were synthesized with a novel binary porogenic agent of polyethylene glycol (PEG)/methanol. The polymer was prepared with (3-(metharyloylamino) propyl) dimethyl (3-sulfopropyl) ammonium hydroxide inner salt (SPP) as monomer, pentaerythritol triacrylate (PETA) as crosslinker, and azobisisobutyronitrile (AIBN) as initiator. In order to optimize the properties, the contents of the polymerization mixture were investigated. The optimum preparation conditions were as follows: the mass ratio of monomer and porogenator = 1:2.5; the mass ratio of SPP and PETA = 1:1 in the monomer; the mass ratio of PEG and methanol = 2:1 in the binary porogenic agent; the content of the initiator (AIBN) = 0.1% (m/m). With the binary porogenic agent of PEG/ methanol addition, good mechanical stability, homogeneous column bed, good permeability and narrow pore size distribution were obtained. In the capillary liquid chromatography mode, the hydrophilic monolith provided column efficiency up to 2.4 x 10(5) plates/m which was much higher than that fabricated by traditional method without PEG/methanol. The columns were used in capillary liquid chromatography and pressurized capillary electrochromatography for the separation of a mixture of phenols, nucleosides and so on. PMID:25069328

  14. Determination of Sudan dyes in chili pepper powder by online solid-phase extraction with a butyl methacrylate monolithic column coupled to liquid chromatography with tandem mass spectrometry.

    PubMed

    Liu, Yao; Wang, Man-Man; Ai, Lian-Feng; Zhang, Chang-Kun; Li, Xin; Wang, Xue-Sheng

    2014-07-01

    A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was fabricated and used as a novel sorbent for online solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry for the simultaneous determination of Sudan I-IV in chili pepper powder. The prepared columns were characterized by scanning electron microscopy, nitrogen adsorption-desorption, and pressure drop measurements. Online solid-phase extraction was performed on the synthesized monolithic column using 10 mM ammonium acetate solution as the loading solution with the aid of an online cleanup chromatography system. The desorption of Sudan I-IV was achieved with acetonitrile as the eluting solution at the flow rate of 0.5 mL/min. The extracted analytes were subsequently eluted into a C18 analytical column for chromatographic separation using a mixture of 10% acetonitrile/90% formic acid (0.5%) solution as the mobile phase. Under the optimized conditions, the developed method had linear range of 1.0-50 μg/kg, a detection limit of 0.3 μg/kg, and a quantification limit of 1.0 μg/kg for each analyte. The intraday and interday recoveries of Sudan I-IV in chili pepper powder samples ranged from 94.8 to 100.9% and 94.9 to 99.4%, respectively. The intraday and interday precision were between 3.37-7.01% and 5.01-7.68%, respectively. PMID:24723310

  15. Chip-based molecularly imprinted monolithic capillary array columns coated GO/SiO2 for selective extraction and sensitive determination of rhodamine B in chili powder.

    PubMed

    Zhai, Haiyun; Huang, Lu; Chen, Zuanguang; Su, Zihao; Yuan, Kaisong; Liang, Guohuan; Pan, Yufang

    2017-01-01

    A novel solid-phase extraction chip embedded with array columns of molecularly imprinted polymer-coated silanized graphene oxide (GO/SiO2-MISPE) was established to detect trace rhodamine B (RB) in chili powder. GO/SiO2-MISPE monolithic columns for RB detection were prepared by optimizing the supporting substrate, template, and polymerizing monomer under mild water bath conditions. Adsorption capacity and specificity, which are critical properties for the application of the GO/SiO2-MISPE monolithic column, were investigated. GO/SiO2-MIP was examined by scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy. The recovery and the intraday and interday relative standard deviations for RB ranged from 83.7% to 88.4% and 2.5% to 4.0% and the enrichment factors were higher than 110-fold. The chip-based array columns effectively eliminated impurities in chili powder, indicating that the chip-based GO/SiO2-MISPE method was reliable for RB detection in food samples using high-performance liquid chromatography. Accordingly, this method has direct applications for monitoring potentially harmful dyes in processed food. PMID:27507523

  16. Determination of Sudan dyes in chili pepper powder by online solid-phase extraction with a butyl methacrylate monolithic column coupled to liquid chromatography with tandem mass spectrometry.

    PubMed

    Liu, Yao; Wang, Man-Man; Ai, Lian-Feng; Zhang, Chang-Kun; Li, Xin; Wang, Xue-Sheng

    2014-07-01

    A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was fabricated and used as a novel sorbent for online solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry for the simultaneous determination of Sudan I-IV in chili pepper powder. The prepared columns were characterized by scanning electron microscopy, nitrogen adsorption-desorption, and pressure drop measurements. Online solid-phase extraction was performed on the synthesized monolithic column using 10 mM ammonium acetate solution as the loading solution with the aid of an online cleanup chromatography system. The desorption of Sudan I-IV was achieved with acetonitrile as the eluting solution at the flow rate of 0.5 mL/min. The extracted analytes were subsequently eluted into a C18 analytical column for chromatographic separation using a mixture of 10% acetonitrile/90% formic acid (0.5%) solution as the mobile phase. Under the optimized conditions, the developed method had linear range of 1.0-50 μg/kg, a detection limit of 0.3 μg/kg, and a quantification limit of 1.0 μg/kg for each analyte. The intraday and interday recoveries of Sudan I-IV in chili pepper powder samples ranged from 94.8 to 100.9% and 94.9 to 99.4%, respectively. The intraday and interday precision were between 3.37-7.01% and 5.01-7.68%, respectively.

  17. The fabrication of monolithic capillary column based on poly (bisphenol A epoxy vinyl ester resin-co-ethylene glycol dimethacrylate) and its applications for the separation of small molecules in high performance liquid chromatography.

    PubMed

    Niu, Wenjing; Wang, Lijuan; Bai, Ligai; Yang, Gengliang

    2013-07-01

    A new polymeric monolith was synthesized in fused-silica capillary by in situ polymerization technique. In the polymerization, bisphenol A epoxy vinyl ester resin (VER) was used as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the crosslinking monomer, 1,4-butanediol, 1-propanol and water as the co-porogens, and azobisisobutyronitrile (AIBN) as the initiator. The conditions of polymerization have been optimized. Morphology of the prepared poly (VER-co-EDMA) monolith was investigated by the scanning electron microscopy (SEM); pore properties were assayed by mercury porosimetry and nitrogen adsorption. The optimized poly (VER-co-EDMA) monolith showed a uniform structure, good permeability and mechanical stability. Then, the column was used as the stationary phase of high performance liquid chromatography (HPLC) to separate the mixture of benzene derivatives. The best column efficiency achieved for phenol was 235790 theoretical plates per meter. Baseline separations of benzene derivatives and halogenated benzene compounds under optimized isocratic mode conditions were achieved with high column efficiency. The column showed good reproducibility: the relative standard deviation (RSD) values based on the retention times (n=3) for run-to-run, column-to-column and batch-to-batch were less than 0.98, 1.68, 5.48%, respectively. Compared with poly (BMA-co-EDMA) monolithic column, the proposed monolith exhibited more efficiency in the separation of small molecules. PMID:23726080

  18. Simultaneous separation of water- and fat-soluble vitamins in isocratic pressure-assisted capillary electrochromatography using a methacrylate-based monolithic column.

    PubMed

    Yamada, Hiroki; Kitagawa, Shinya; Ohtani, Hajime

    2013-06-01

    A method of simultaneous separation of water- and fat-soluble vitamins using pressure-assisted CEC with a methacrylate-based capillary monolithic column was developed. In the proposed method, water-soluble vitamins were mainly separated electrophoretically, while fat soluble-ones were separated chromatographically by the interaction with a methacrylate-based monolith. A mixture of six water-soluble and four fat-soluble vitamins was separated simultaneously within 20 min with an isocratic elution using 1 M formic acid (pH 1.9)/acetonitrile (30:70, v/v) containing 10 mM ammonium formate as a mobile phase. When the method was applied to a commercial multivitamin tablet and a spiked one, the vitamins were successfully analyzed, and no influence of the matrix contained in the tablet was observed.

  19. MicroSPE-nanoLC-ESI-MS/MS Using 10-μm-i.d. Silica-Based Monolithic Columns for Proteomics

    SciTech Connect

    Luo, Quanzhou; Page, Jason S.; Tang, Keqi; Smith, Richard D.

    2007-01-01

    Silica-based monolithic narrow bore capillary columns (25 cm x 10 µm i.d.) with an integrated nanoESI emitter has been developed to provide high quality and robust microSPE-nanoLC-ESI-MS analyses. The integrated nanoESI emitter adds no dead volume to the LC separation, allowing stable electrospray performance to be obtained at flow rates of ~10 nL/min. In an initial application we identified 5510 unique peptides covering 1443 distinct Shewanella oneidensis proteins from a 300 ng tryptic digest sample in a single 4-h LC-MS/MS analysis using a linear ion trap MS (LTQ). We found the use of an integrated monolithic ESI emitter provided enhanced resistance to clogging and good run-to-run reproducibility.

  20. Simultaneous determination of dibucaine and naphazoline in human serum by monolithic silica spin column extraction and liquid chromatography-mass spectrometry.

    PubMed

    Saito, Takeshi; Morita, Seiji; Kishiyama, Izumi; Miyazaki, Shota; Nakamoto, Akihiro; Nishida, Manami; Namera, Akira; Nagao, Masataka; Inokuchi, Sadaki

    2008-09-01

    A simple, sensitive, and specific liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of dibucaine and naphazoline from serum was developed and validated. The extraction procedure was performed using a monolithic silica spin column. Chromatographic separation of dibucaine and naphazoline was achieved on a C(18) reverse phase column with a mobile phase gradient (mobile phase A: 10 mM ammonium formate and mobile phase B: acetonitrile) at a flow rate of 0.2 mL/min. LC-MS was operated under the selective ion monitoring mode using the electrospray ionization technique in the positive mode. The retention times for naphazoline, dibucaine, and the internal standard (IS) were 6.7, 7.8, and 8.0 min, respectively. A linear graph was obtained for dibucaine and naphazoline with correlation coefficients >0.998 for all analytes by this method. The limit of quantification of dibucaine and naphazoline was 10 and 25 ng/mL, respectively. The mean recoveries were greater than 70%. Both compounds were stable under conditions of short-term storage, long-term storage as well as after freeze-thaw cycles. Monolithic spin column extraction and LC-MS analysis enabled the separation of dibucaine and naphazoline within 20 min.

  1. Monolithic poly (SPE-co-BVPE) capillary columns as a novel hydrophilic interaction liquid chromatography stationary phase for the separation of polar analytes.

    PubMed

    Foo, Hsiao Ching; Heaton, James; Smith, Norman W; Stanley, Shawn

    2012-10-15

    A novel hydrophilic interaction liquid chromatography (HILIC) stationary phase was prepared by the co-polymerisation of zwitterionic N,N'-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) ammonium betaine (SPE) and the crosslinker 1,2-bis(p-vinylphenyl) ethane (BVPE) in the presence of the porogens, toluene and methanol. Monolithic columns were produced by carrying out the α,α'-azoisobutyronitrile (AIBN) initiated reaction for 1, 2, 4, 8 and 12 h inside a 200 μm i.d. fused silica capillary at 75°C (water bath). The optimum polymerisation time was shown to be 2 h, as this resulted in good porosity, due to enlarged flow-channels and the presence of a higher proportion of mesopores provided a relatively larger surface area than the other columns. The chromatographic properties of the optimised poly (SPE-co-BVPE) monolithic column were evaluated with test mixtures containing both basic and neutral compounds in the HILIC gradient separation mode. This produced relatively sharp peaks (average peak width at half height=0.1 min) with average asymmetry factors of 1.4 and baseline resolution was obtained for all the compounds. Using the isocratic separation of the test mixture, the number of theoretical plates (N) per metre calculated was between 26,888 and 35,930 by using average values obtained for triplicate injections of the compounds thiourea, toluene and acrylamide.

  2. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    PubMed

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-01

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  3. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    PubMed

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-01

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  4. Semi-micro reversed-phase liquid chromatography for the separation of alkyl benzenes and proteins exploiting methacrylate- and polystyrene-based monolithic columns.

    PubMed

    Masini, Jorge Cesar

    2016-05-01

    Monolithic columns were synthesized inside 1.02 mm internal diameter fused-silica lined stainless-steel tubing. Styrene and butyl, hexyl, lauryl, and glycidyl methacrylates were the functional monomers. Ethylene glycol dimethacrylate and divinylbenzene were the crosslinkers. The glycidyl methacrylate polymer was modified with gold nanoparticles and dodecanethiol (C12 ). The separation of alkylbenzenes was investigated by isocratic elution in 60:40 v/v acetonitrile/water. The columns based on polystyrene-co-divinylbenzene and poly(glycidyl methacrylate)-co-ethylene glycol dimethacrylate modified with dodecanethiol did not provide any separation of alkyl benzenes. The poly(hexyl methacrylate)-co-ethylene glycol dimethacrylate and poly(lauryl methacrylate)-co-ethylene glycol dimethacrylate columns separated the alkyl benzenes with plate heights between 30 and 60 μm (50 μL min(-1) and 60°C). Similar efficiency was achieved in the poly(butyl methacrylate)-co-ethylene glycol dimethacrylate column, but only at 10 μL min(-1) (0.22 mm s(-1) ). Backpressures varied from 0.38 MPa in the hexyl methacrylate to 13.4 MPa in lauryl methacrylate columns (50 μL min(-1) and 60°C). Separation of proteins was achieved in all columns with different efficiencies. At 100 μL min(-1) and 60°C, the lauryl methacrylate columns provided the best separation, but their low permeability prevented high flow rates. Flow rates up to 500 μL min(-1) were possible in the styrene, butyl and hexyl methacrylate columns.

  5. Preparation and evaluation of monolithic poly(N-vinylcarbazole-co-1,4-divinylbenzene) capillary columns for the separation of small molecules.

    PubMed

    Koeck, Rainer; Fischnaller, Martin; Bakry, Rania; Tessadri, Richard; Bonn, Guenther K

    2014-09-01

    Short-term polymerization or the so-called low-conversion polymerization was applied for the preparation of N-vinylcarbazole (NVC) and 1,4-divinylbenzene (DVB) monolithic capillary columns. The synthesis was carried out by thermally initiated free radical copolymerization under the influence of inert micro- (toluene) and macroporogen (1-decanol) and α,α'-azoisobutyronitrile (AIBN) as radical initiator. The morphological and porous properties were studied by scanning electron microscopy (SEM), nitrogen adsorption, and mercury intrusion porosimetry (MIP). The copolymerization process was studied by monomer conversion measurements. This approach led to increased porosity and specific surface area. A specific surface area above 400 m(2)/g of the monolith and a distinct bimodal pore size distribution were obtained. The chromatographic performance was determined in terms of theoretical plate heights and number of theoretical plates. The lowest plate height value was found to be 3.9 μm (corresponding to ≈256,000 plates per meter) applying methylparaben utilizing an 80 mm × 0.2 mm i.d. monolithic capillary. The developed NVC/DVB monolithic supports showed high separation efficiency towards small molecules, which was exemplified applying reversed-phase (RP) separation of alkylbenzenes, beta-blockers, flavanoids, parabens, and phenones. The loading capacity was analyzed for isocratic separation of seven alkylbenzenes and was found to be up to 77 ng total mass of alkylbenzenes. Furthermore, a long-term stability test of 1,000 consecutive runs was performed and resulted in a maximum variance of 0.97, 0.85, and 0.16 % RSD for resolution, peak width at half height, and retention times, respectively. The material was proven to have a high permeability of 1.11E-14 m(2), applying water as a mobile phase. PMID:25056873

  6. Monolithic metal-organic framework MIL-53(Al)-polymethacrylate composite column for the reversed-phase capillary liquid chromatography separation of small aromatics.

    PubMed

    Yusuf, Kareem; Badjah-Hadj-Ahmed, Ahmed Yacine; Aqel, Ahmad; ALOthman, Zeid Abdullah

    2016-03-01

    A monolithic capillary column containing a composite of metal-organic framework MIL-53(Al) incorporated into hexyl methacrylate-co-ethylene dimethacrylate was prepared to enhance the separation of mixtures of small aromatic compounds by using capillary liquid chromatography. The addition of 10 mg/mL MIL-53(Al) microparticles increased the micropore content in the monolithic matrix and increased the Brunauer-Emmett-Teller surface area from 26.92 to 85.12 m(2) /g. The presence of 1,4-benzenedicarboxylate moieties within the structure of MIL-53(Al) as an organic linker greatly influenced the separation of aromatic mixtures through π-π interactions. High-resolution separation was obtained for a series of alkylbenzenes (with resolution factors in the range 0.96-1.75) in less than 8 min, with 14 710 plates/m efficiency for propylbenzene, using a binary polar mobile phase of water/acetonitrile in isocratic mode. A reversed-phase separation mechanism was indicated by the increased retention factor and resolution as the water percentage in the mobile phase increased. A stability study on the composite column showed excellent mechanical stability under various conditions. The higher resolution and faster separation observed at increased temperature indicated an exothermic separation, whereas the negative values for the free energy change of transfer indicated a spontaneous process.

  7. Porous molecularly imprinted monolithic capillary column for on-line extraction coupled to high-performance liquid chromatography for trace analysis of antimicrobials in food samples.

    PubMed

    Zhang, Qianchun; Xiao, Xiaohua; Li, Gongke

    2014-06-01

    A novel porous molecularly imprinted monolithic capillary column (MIMCC) based on ternary porogen was synthesized by in situ technique with sulfaquinoxaline as the template molecule. The characteristics of the MIMCC were investigated by scanning electron microscopy, infrared spectrum, thermogravimetric analysis and solvent resistance test. The saturated adsorption amount of sulfaquinoxaline on MIMCC was 2.7 times over that on the non-imprinted monolithic capillary column (NIMCC). The MIMCC also exhibited good enrichment ability to its analogs and the enrichment factors were 46-211 for five antimicrobials. High permeability and imprinting factors as well as good stability, reproducibility and long lifetime were obtained. An on-line method based on MIMCC solid-phase microextraction coupled with high-performance liquid chromatography was developed for the determination of trace antimicrobials in complex samples. The good linearity for sulfametoxydiazine, sulamethoxazole and sulfaquinoxaline was 0.05-10 µg/L, the limits of detection (LODs) were 10.0-14.0 ng/L. The linear range for mequindox and quinocetone were 0.10-10.0 µg/L, the LODs were 20.0-27.0 ng/L respectively. The recoveries were 71.0-108.2% with relative standard deviation of 1.6-8.5%, correspondingly. The results showed that MIMCC could effectively enrich antimicrobials from complex matrices. The on-line method based on MIMCC and HPLC was selective, sensitive and convenient for trace determination of antimicrobials in complex samples. PMID:24725865

  8. [Determination of five avermectins in bovine liver by on-line solid-phase extraction with hydrophobic monolithic column coupled with high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Li, Xin; Zhang, Yaoqin; Ai, Lianfeng; Wang, Xuesheng; Wang, Manman; Xu, Houjun; Hao, Yulan

    2015-06-01

    A method based on on-line solid-phase extraction (SPE) with hydrophobic monolithic column coupled with high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of five avermectins in bovine liver. A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was used as the sorbent. The parameters influenced on on-line SPE and separation process such as the loading mobile phase, the eluting flow rate and the solvent for the separation were investigated in detail. Blank samples, spiked samples, matrix effect and recovery experiments were investigated to evaluate the extraction efficiency and potential interfering compounds originating from the matrix. Under the optimized conditions, the method showed a linear range of 1-100 µg/L and the quantification limit of 5 µg/kg for each analyte. The presented method gave recoveries of 77.4%-98.4%. The relative standard deviations of intra-day and inter-day were 4.46%-8.03% and 4.79%-8.68%, respectively. Moreover, no significant changes were found in the extraction performance after more than 400 usages on one monolithic column, and even on the monoliths with various batches. The feasibility of the developed poly (butyl methacrylate-coethylene dimethacrylate) monolithic column based on the on-line SPE method for the determination of avermectins was further demonstrated by the analysis of real samples.

  9. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    ERIC Educational Resources Information Center

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  10. Purification of monoclonal antibodies, IgG1, from cell culture supernatant by use of metal chelate convective interaction media monolithic columns.

    PubMed

    Rajak, Poonam; Vijayalakshmi, M A; Jayaprakash, N S

    2012-12-01

    Monoclonal antibodies (MAbs) have diverse applications in diagnostics and therapeutics. The recent advancement in hybridoma technology for large-scale production of MAbs in bioreactors demands rapid and efficient purification methods. Conventional affinity purification systems have drawbacks of low flow rates and denaturation of antibodies owing to harsh elution conditions. Here, we attempted purification of MAbs by use of a high-throughput metal-chelate methacrylate monolithic system. Monolithic macroporous convective interaction media-iminodiacetate (CIM-IDA) disks immobilized with four different metal ions (Cu²⁺, Ni²⁺, Zn²⁺ and Co²⁺) were used and evaluated for purification of anti-human serum albumin IgG1 mouse MAbs from cell culture supernatant after precipitation with 50% ammonium sulfate. Elution with 10 mM imidazole in the equilibration buffer (25 mM MMA = MOPS (Morpholino propane sulfonic acid) + MES (Morpholino ethane sulfonic acid) + Acetate + 0.5 M NaCl, pH 7.4) resulted in a purification of 25.7 ± 2.9-fold and 32.5 ± 2.6-fold in experiments done using Zn²⁺ and Co²⁺ metal ions, respectively. The highest recovery of 85.4 ± 1.0% was obtained with a CIM-IDA-Zn(II) column. SDS-PAGE, ELISA and immuno-blot showed that the antibodies recovered were pure, with high antigen-binding efficiency. Thus, metal chelate CIM monoliths could be a potential alternative to conventional systems for fast and efficient purification of MAbs from the complex cell culture supernatant. PMID:22362585

  11. More sensitive and quantitative proteomic measurements using very low flow rate porous silica monolithic LC columns with electrospray ionization-mass spectrometry

    SciTech Connect

    Luo, Quanzhou; Tang, Keqi; Yang, Feng; Elias, Ayesha; Shen, Yufeng; Moore, Ronald J.; Zhao, Rui; Hixson, Kim K.; Rossie, Sandra S.; Smith, Richard D.

    2006-05-01

    The sensitivity of proteomics measurements using liquid chromatography (LC) separations interfaced with electrospray ionization-mass spectrometry (ESI-MS) improves approximately inversely with liquid flow rate, making attractive the use of smaller inner diameter LC columns. We report the development and initial application of 10 µm i.d. silica-based monolithic LC columns providing more sensitive proteomics measurements. The implementation provides robust performance and suitability for automated proteome analyses due to integration with a micro solid phase extraction pre-column for ease of sample injection and clean-up prior to the reversed phased LC separation. Greater than 10-fold improvement in sensitivity was obtained compared to analyses using more conventional capillary LC, enabling e.g. the identification of >5000 different peptides by MS/MS from 100-ng of a Shewanella oneidensis tryptic digest using an ion trap MS. The low nL/min LC flow rates provide more uniform signal intensities for different peptides, and provided improved quantitative measurements compared to conventional separation systems without the use of internal standards or isotopic labeling. The improved sensitivity allowed LC-MS measurements of immunopurified protein phosphatase 5 that were in good agreement with quantitative western blot analyses.

  12. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance. PMID:26916593

  13. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance.

  14. Porous polymer monoliths with large surface area and functional groups prepared via copolymerization of protected functional monomers and hypercrosslinking.

    PubMed

    Maya, Fernando; Svec, Frantisek

    2013-11-22

    A new approach to the preparation of porous polymer monoliths possessing both large surface area and functional groups has been developed. The chloromethyl groups of poly(styrene-co-4-acetoxystyrene-co-vinylbenzyl chloride-co-divinylbenzene) monolith enable post-polymerization hypercrosslinking catalyzed by ferric chloride in dichloroethane leading to a multitude of small pores thus enhancing the surface area. The acetoxy functionalities are easily deprotected using hydrazine to produce polar phenolic hydroxyl groups, which would be difficult to obtain by direct copolymerization of hydroxyl-containing monomers. The hypercrosslinking and deprotection reactions as well as their sequence were studied in detail with bulk polymer monoliths containing up to 50% 4-acetoxystyrene and its progress monitored by infrared spectrometry and nitrogen adsorption/desorption measurements. No significant difference was found for both possible successions. All monoliths were also prepared in a capillary column format, then deprotected and hypercrosslinked. Capillary columns were tested for the separation of small molecules using reversed phase and normal phase chromatographic modes. For polymer monoliths containing 50% deprotected 4-acetoxystyrene, column efficiencies of 40,000 plates/m for benzene in reversed phase mode and 31,800 plates/m for nitrobenzene in normal phase mode, were obtained. The percentage of hydroxyl groups in the monoliths enables modulation of polarity of the stationary phase. They also represent functionalities that are potentially suitable for further modifications and formation of new types of stationary phases for liquid chromatography.

  15. Pressurized CEC with amperometric detection using mixed-mode monolithic column for rapid analysis of chlorophenols and phenol.

    PubMed

    Lu, Lanxiang; Chen, Yankai; Yu, Xiaowei; Wu, Xiangzong; Tang, Fengxiang; Wu, Xiaoping

    2013-07-01

    A simple analysis of chlorophenols (2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol) and phenol was accomplished by coupling a pressurized CEC with amperometric detection (AD). Efficient and reproducible separation of these compounds was achieved within 9 min on a capillary monolithic stationary phase bonded with octadecyl ligands and sulfonate groups, where the selectivity and the retention of analytes can be functionally controlled by optimizing experimental variables, including organic modifier content, mobile phase pH, ionic strength, working electrode potential, separation voltage, and supplementary pressure. A mixed-mode retention mechanism consisting of reverse-phase chromatographic partition, electrostatic repulsion, and electrophoresis is considered to play roles in the separation. The use of ACN-based media seems effectual in preventing the unfavorable irreversible adsorption on both wall and electrode, and offer higher sensitivity and less electrode fouling in AD of phenols. The LODs were in the range from 0.02 to 0.2 μg/mL with a wide linear dynamic range of 5000-fold, while the peak area precision ranged from 3.2 to 7.5%. The feasibility of using this method in real analysis was evaluated by recovery estimates and comparative experiment on spiked tap water samples. Good recoveries of 80-110% were achieved. Additionally, a paired t-test was used to correlate the two methods.

  16. Selective microemulsion liquid chromatography analysis of dopamine receptor antagonist LE300 and its N-methyl metabolite in mouse sera by using a monolithic silica column.

    PubMed

    Al-Majed, Abdulrhman A; Hefnawy, Mohamed M; Mohammed, Mostafa S; Attia, Sabry M; Lehmann, Jochen

    2015-05-01

    A highly selective, sensitive, and rapid microemulsion liquid chromatography (MELC) method was developed and validated for the simultaneous determination of a novel type of dopamine receptor antagonist LE300 and its N-methyl metabolite in mouse sera. LE300, its N-methyl metabolite, and pindolol (an internal standard) were detected using excitation and emission wavelengths of 275 and 340 nm, respectively. HPLC analysis by using a monolithic column was performed by directly injecting the sample after appropriate dilution with the microemulsion mobile phase. The chromatographic behaviour of these compounds was studied to demonstrate their chromatographic efficiency, retention, and peak symmetry. The MELC method was validated for its specificity, linearity, accuracy, precision, robustness and stability. An experimental design was used during validation to evaluate method robustness. The calibration curves in serum showed excellent linearity (r=0.997) over concentrations ranging from 10 to 400 ngmL(-1) for LE300 and 15 to 500 ngmL(-1) for its N-methyl metabolite. The mean relative standard deviation (RSD) of the results of inter- and intra-day precision and accuracy of LE300 and its N-methyl metabolite were ≤5%. The overall recoveries of LE300 and its N-methyl metabolite from mouse sera were in the range 97.9-101.5% with %RSD ranging from 0.98% to 3.63%, which were in line with ICH guidelines. The assay was successfully applied in a pharmacokinetic study.

  17. Simultaneous determination of antioxidants, preservatives and sweetener additives in food and cosmetics by flow injection analysis coupled to a monolithic column.

    PubMed

    García-Jiménez, J F; Valencia, M C; Capitán-Vallvey, L F

    2007-07-01

    Today it is common to find samples with various additives from several families. This is the case of sweeteners, preservatives and antioxidants. We have selected a set of additives broadly used in foods and cosmetics with an ample variety of polarities, namely: aspartame (AS), acesulfame (AK)/saccharin (SA), methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), propylgallate (PG) and butylhydroxyanisole (BA). The monolithic column used as separative system is a 5 mm commercial precolumn of silica C18 coupled to a flow injection manifold working with a peristaltic pump. The mixture was separated in only 400 s with resolution factors greater than 1.1 in all cases. To achieve the separation in the FIA system we used two carriers: first, a mixture of ACN/water buffered with 10 mM pH 6.0 phosphate buffer and second, a methanol:water mixture to improve the carrier strength and speed up the more apolar analytes at 3.5 mL min(-1). Detection is accomplished by means of a diode array spectrometer at the respective wavelength of each compound. The comparison of the analytical parameters obtained for this procedure with a standard HPLC method validates our new method, obtaining a method that is quick, with high repeatability and reproducibility and with good resolution between analytes. We have successfully applied the method to real food and cosmetics samples.

  18. Effect of pore water velocities and solute input methods on chloride transport in the undisturbed soil columns of Loess Plateau

    NASA Astrophysics Data System (ADS)

    Zhou, BeiBei; Wang, QuanJiu

    2016-04-01

    Studies on solute transport under different pore water velocity and solute input methods in undisturbed soil could play instructive roles for crop production. Based on the experiments in the laboratory, the effect of solute input methods with small pulse input and large pulse input, as well as four pore water velocities, on chloride transport in the undisturbed soil columns obtained from the Loess Plateau under controlled condition was studied. Chloride breakthrough curves (BTCs) were generated using the miscible displacement method under water-saturated, steady flow conditions. Using the 0.15 mol L-1 CaCl2 solution as a tracer, a small pulse (0.1 pore volumes) was first induced, and then, after all the solution was wash off, a large pulse (0.5 pore volumes) was conducted. The convection-dispersion equation (CDE) and the two-region model (T-R) were used to describe the BTCs, and their prediction accuracies and fitted parameters were compared as well. All the BTCs obtained for the different input methods and the four pore water velocities were all smooth. However, the shapes of the BTCs varied greatly; small pulse inputs resulted in more rapid attainment of peak values that appeared earlier with increases in pore water velocity, whereas large pulse inputs resulted in an opposite trend. Both models could fit the experimental data well, but the prediction accuracy of the T-R was better. The values of the dispersivity, λ, calculated from the dispersion coefficient obtained from the CDE were about one order of magnitude larger than those calculated from the dispersion coefficient given by the T-R, but the calculated Peclet number, Pe, was lower. The mobile-immobile partition coefficient, β, decreased, while the mass exchange coefficient increased with increases in pore water velocity.

  19. Separation of N-derivatized di- and tri-peptide stereoisomers by micro-liquid chromatography using a quinidine-based monolithic column - Analysis of l-carnosine in dietary supplements.

    PubMed

    Wang, Qiqin; Sánchez-López, Elena; Han, Hai; Wu, Huihui; Zhu, Peijie; Crommen, Jacques; Marina, Maria Luisa; Jiang, Zhengjin

    2016-01-01

    In the present study, a new analytical methodology was developed enabling the enantiomeric determination of N-derivatized di- and tri-peptides in dietary supplements using chiral micro-LC on a monolithic column consisting of poly(O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (poly(MQD-co-HEMA-co-EDMA)). After optimization of the mobile phase conditions, a baseline resolution of the stereoisomers of 24 out of 53 N-derivatized di- and tri-peptides was obtained. 3,5-Dinitrobenzoyl- and 3,5-dichlorobenzoyl-peptide stereoisomers were separated with exceptionally high selectivity and resolution. The monolithic column was then applied to the quantitative analysis of l-carnosine and its enantiomeric impurity in three different commercial dietary supplements. Method validation demonstrated satisfactory results in terms of linearity, precision, selectivity, accuracy and limits of detection and quantification. The determined amounts of l-carnosine in commercial formulations were in agreement with the labeled content for all analyzed samples, and the enantiomeric impurity was found to be below the limit of detection (LOD), showing the potential of the poly(MQD-co-HEMA-co-EDMA) monolithic column as a reliable tool for the quality control of l-carnosine in dietary supplements by micro-LC.

  20. Fast analysis using monolithic columns coupled with high-flow on-line extraction and electrospray mass spectrometric detection for the direct and simultaneous quantitation of multiple components in plasma.

    PubMed

    Zeng, Hang; Deng, Yuzhong; Wu, Jing-Tao

    2003-05-25

    In this work, monolithic columns were used as a fast separation tool for multiple-component quantitative liquid chromatography-tandem mass spectrometry (LC-MS-MS) assays of drug candidates in biological fluids. A considerably reduced runtime was achieved while maintaining good chromatographic separations. This significantly improved separation speed demanded higher throughput on sample extraction. To this end, monolithic separations were coupled on-line with high-flow extraction, which allowed for the fast extraction and separation of samples containing multiple analytes. An evaluation of this system was performed using a mixture of fenfluramine, temazepam, oxazepam, and tamoxifen in plasma. A total cycle time of 1.2 min was achieved which included both sample extraction and subsequent monolithic column separation via column switching. A total of over 400 plasma samples were analyzed in less than 10 h. The sensitivity and responses were reproducible throughout the run. The system has been routinely used in the authors' laboratory for high-throughput quantitation of compounds in biological fluids in support of drug discovery programs. The assay for samples from a 9-in-1 dog pharmacokinetic study is shown as an example to demonstrate the capability of this system. PMID:12705973

  1. Rapid fabrication of ionic liquid-functionalized monolithic column via in-situ urea-formaldehyde polycondensation for pressurized capillary electrochromatography.

    PubMed

    Wang, Jiabin; Wu, Fangling; Xia, Ruirui; Zhao, Qi; Lin, Xucong; Xie, Zenghong

    2016-06-01

    A novel strategy for rapidly fabricating ionic liquid (IL)-bonded multifunctional monolithic stationary phase has been developed by an in-situ polycondensation of urea-formaldehyde (UF) and a lab-made acylamino-functionalized IL (1-acetylamino-propyl-3-methylimidazolium bromide, [AAPMIm]Br). Two polycondensation processes of UF with 1-amino-propyl-3-methylimidazolium bromide or [AAPMIm]Br were evaluated. Several parameters including mass ratio of urea-formaldehyde, amount of [AAPMIm]Br, polycondensation time and reaction temperature were optimized, and the [AAPMIm]Br-bonded monolithic stationary phase could be rapidly synthesized in 10min with a satisfactory permeability and mechanical stability. Used for pressurized capillary electrochromatography (pCEC), a typical hydrophilic interaction (HI) retention could be obtained in the resultant [AAPMIm]Br-bonded monolith when the content of acetonitrile (ACN) in mobile phase exceeded 20%. Multiple retention mechanisms such as hydrophilic interaction (HI), hydrogen bond (HH), anion-exchange and cation-exclude interactions, were acheived in the [AAPMIm]Br-bonded monolith. Various polar compounds including phenols, benzoic acid and its homologues, and enkephalins have been well separated and thus demonstrated a satisfactory separation performance of the obtained monolith. A facile access is lighted for rapid preparation of ionic liquid-bonded monoliths with multiple retention mechanisms for pCEC. PMID:27156751

  2. Green synthesis of polymer monoliths incorporated with carbon nanotubes in room temperature ionic liquid and deep eutectic solvents.

    PubMed

    Zhang, Li-Shun; Gao, Shu-Ping; Huang, Yan-Ping; Liu, Zhao-Sheng

    2016-07-01

    In this work, an efficient method to prepare polymer monoliths with incorporated carbon nanotubes in a mixture of room temperature ionic liquid and deep eutectic solvents was developed. With assistance of the binary green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate and choline chloride/ethylene glycol, single-walled carbon nanotubes were dispersed successfully in pre-polymerization mixture without need of oxidative cutting of carbon nanotubes, which may allow depletion of the emission of volatile organic compounds into environment. The novel single-walled carbon nanotubes monolith was evaluated by capillary electrochromatography. Compared with the monolith made without single-walled carbon nanotubes, the monolith with the incorporation of single-walled carbon nanotubes exhibited high column efficiency (251,000plates/m) in the chromatographic separation. The morphology of the monolith can be tuned by the composition of mixture of ionic liquids and deep eutectic solvents to afford good column permeability and excellent separation ability for small molecules of alkyl phenones and alkyl benzenes. The results demonstrated that the method is a green strategy for the fabrication of multifunctional polymer monoliths. PMID:27154683

  3. Green synthesis of polymer monoliths incorporated with carbon nanotubes in room temperature ionic liquid and deep eutectic solvents.

    PubMed

    Zhang, Li-Shun; Gao, Shu-Ping; Huang, Yan-Ping; Liu, Zhao-Sheng

    2016-07-01

    In this work, an efficient method to prepare polymer monoliths with incorporated carbon nanotubes in a mixture of room temperature ionic liquid and deep eutectic solvents was developed. With assistance of the binary green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate and choline chloride/ethylene glycol, single-walled carbon nanotubes were dispersed successfully in pre-polymerization mixture without need of oxidative cutting of carbon nanotubes, which may allow depletion of the emission of volatile organic compounds into environment. The novel single-walled carbon nanotubes monolith was evaluated by capillary electrochromatography. Compared with the monolith made without single-walled carbon nanotubes, the monolith with the incorporation of single-walled carbon nanotubes exhibited high column efficiency (251,000plates/m) in the chromatographic separation. The morphology of the monolith can be tuned by the composition of mixture of ionic liquids and deep eutectic solvents to afford good column permeability and excellent separation ability for small molecules of alkyl phenones and alkyl benzenes. The results demonstrated that the method is a green strategy for the fabrication of multifunctional polymer monoliths.

  4. Monolithic Domes.

    ERIC Educational Resources Information Center

    Lanham, Carol

    2002-01-01

    Describes how the energy savings, low cost, and near-absolute protection from tornadoes provided by monolithic domes is starting to appeal to school districts for athletic and other facilities, including the Italy (Texas) Independent School District. Provides an overview of monolithic dome construction. (EV)

  5. Evaluation of interactions between metal ions and nonionic surfactants in high-concentration HCl using low-pressure high-performance liquid chromatography with low-flow-resistance polystyrene-based monolithic column.

    PubMed

    Hirano, Tomohiko; Kitagawa, Shinya; Ohtani, Hajime; Kinoshita, Takehiko; Ishigaki, Yuzo; Shibata, Nobuyuki; Nii, Susumu

    2013-10-01

    A method for evaluating the interactions between metal ions and nonionic surfactants in aqueous solutions containing high-concentration HCl, using gas pressure-driven low-pressure high-performance liquid chromatography (LP-HPLC) as a highly acid-resistant HPLC system, was developed. To construct the LP-HPLC for this purpose, poly(styrene-co-divinylbenzene)-based low-flow-resistance monolithic columns tolerant to highly acidic conditions were prepared using low-conversion thermal polymerization. Thermal polymerization at 65 °C for 1.5 h (monomer conversions, 33% for styrene and 59% for divinylbenzene) allowed preparation of a column with both high separation efficiency (around 60,000 plates m(-1) for alkylbenzenes) and a quite low back pressure of 0.14 MPa at a linear flow rate of 1 mm s(-1) (2.8 × 10(-13) m(2) in permeability). The base column prepared under the above conditions was coated with a nonionic surfactant, polyoxyethylene nonylphenyl ether (PONPE, average oxyethylene unit numbers (n) = 3, 7.5, 15, and 20), and used for evaluation of the interactions between PONPEs and metal ions in 6 M HCl. The interactions between PONPEs and Au(III), Ga(III), Fe(III), Zn(II), and Cu(II) were successfully evaluated using both breakthrough and chromatographic methods. Furthermore, a study of the effect of the polyoxyethylene (POE) chain length revealed that the use of PONPE with the longer POE moiety enhanced the magnitude of the interaction together with the increase in the amount of oxyethylene (OE) units coated on the monolith. Moreover, the interactions of metal ions with a single OE unit were almost constant in the range of n = 7.5-20, whereas the suppression of the interaction between Au(III) with the shortest PONPE chain (n = 3) was also observed. PMID:23884474

  6. Preparation of 2,4-dichlorophenoxyacetic acid imprinted organic-inorganic hybrid monolithic column and application to selective solid-phase microextraction.

    PubMed

    Liu, Xiaofang; Zhu, Quanfei; Chen, Huaixia; Zhou, Liuzi; Dang, Xueping; Huang, Jianlin

    2014-03-01

    An organic-inorganic hybrid molecular imprinting monolith (HMIM) has been prepared, characterized and applied for the determination of 2,4-dichlorophenoxyacetic acid (2,4-D) in rice with high-performance liquid chromatography-photodiodes array detector (HPLC-PAD). By optimizing the polymerization conditions, such as the volume ratio of the inorganic alcoholysate and organic part, the 2,4-D-HMIM was synthesized in a micro pipette tip using acrylamide as the functional monomer, ethylene dimethacrylate as the cross-linker and methanol as the porogenic solvent. The morphology of the monolith was studied by scanning electronmicroscopy and Fourier transform infrared spectra. The imprinted factor of the monolith for 2,4-D reached 3.29. A simple, rapid and sensitive method for the determination of 2,4-D in rice using the HMIM microextraction combined with high-performance liquid chromatography-photodiodes array detector was developed. Some parameters affecting the sample pretreatment were investigated, including the type and volume of eluent, the flow rate and volume of sample solution. The assay exhibited a linear dynamic range of 167-4167μg/kg with the correlation coefficient above 0.9972. The detection limit (at S/N=3) was 50μg/kg. The proposed method was successfully applied for the selective determination of 2,4-D in rice.

  7. Preparation of hydrophilic monolithic capillary column by in situ photo-polymerization of N-vinyl-2-pyrrolidinone and acrylamide for highly selective and sensitive enrichment of N-linked glycopeptides.

    PubMed

    Jiang, Hao; Yuan, Huiming; Qu, Yanyan; Liang, Yu; Jiang, Bo; Wu, Qi; Deng, Nan; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-01-01

    In this study, a novel kind of amide functionalized hydrophilic monolith was synthesized by the in situ photo-polymerization of N-vinyl-2-pyrrolidinone (NVP), acrylamide (AM), and N, N'-methylenebisacrylamide (MBA) in a UV transparent capillary, and successfully applied for hydrophilic interaction chromatography (HILIC) based enrichment of N-linked glycopeptides. With 2 μg of the tryptic digests of IgG as the sample, after enrichment, 18 glycopeptides could be identified by MALDI-TOF/TOF MS analysis. Furthermore, with the mixture of BSA and IgG digests (10,000:1, m/m) as the sample, 6 N-linked glycopeptides were unambiguously identified after enrichment, indicating the high selectivity and good specificity of such material. Moreover, such a monolithic capillary column was also applied for the N-glycosylation sites profiling of 6 μg protein digests from HeLa cells and 1 μL human serum. In total, 530 and 262 unique N-glycosylated peptides were identified, respectively, corresponding to 282 and 124N-glycoproteins, demonstrating its great potential for the large scale glycoproteomics analysis.

  8. Preparation of hydrophilic monolithic capillary column by in situ photo-polymerization of N-vinyl-2-pyrrolidinone and acrylamide for highly selective and sensitive enrichment of N-linked glycopeptides.

    PubMed

    Jiang, Hao; Yuan, Huiming; Qu, Yanyan; Liang, Yu; Jiang, Bo; Wu, Qi; Deng, Nan; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-01-01

    In this study, a novel kind of amide functionalized hydrophilic monolith was synthesized by the in situ photo-polymerization of N-vinyl-2-pyrrolidinone (NVP), acrylamide (AM), and N, N'-methylenebisacrylamide (MBA) in a UV transparent capillary, and successfully applied for hydrophilic interaction chromatography (HILIC) based enrichment of N-linked glycopeptides. With 2 μg of the tryptic digests of IgG as the sample, after enrichment, 18 glycopeptides could be identified by MALDI-TOF/TOF MS analysis. Furthermore, with the mixture of BSA and IgG digests (10,000:1, m/m) as the sample, 6 N-linked glycopeptides were unambiguously identified after enrichment, indicating the high selectivity and good specificity of such material. Moreover, such a monolithic capillary column was also applied for the N-glycosylation sites profiling of 6 μg protein digests from HeLa cells and 1 μL human serum. In total, 530 and 262 unique N-glycosylated peptides were identified, respectively, corresponding to 282 and 124N-glycoproteins, demonstrating its great potential for the large scale glycoproteomics analysis. PMID:26695256

  9. Monolithic spectrometer

    DOEpatents

    Rajic, S.; Egert, C.M.; Kahl, W.K.; Snyder, W.B. Jr.; Evans, B.M. III; Marlar, T.A.; Cunningham, J.P.

    1998-05-19

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays. 6 figs.

  10. Monolithic spectrometer

    DOEpatents

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  11. Simultaneous determination of tylosin and josamycin residues in muscles, liver, eggs and milk by MLC with a monolithic column and time-programmed UV detection: application to baby food and formulae

    PubMed Central

    2014-01-01

    Background Tylosin and Josamycin are macrolide antibiotics. They are used in the treatment of pneumonia, arthritis and mastitis in cattle, and mycoplasma infections in poultry. The incorrect use of antibiotics has lead to the presence of antibiotic residues in foods. The residues cause toxic effects on consumers. Results A simple and sensitive method was optimized and validated for the analysis of tylosin and josamycin residues in food samples. Analytical separation was performed in less than 10 min using a RP C18 monolithic column with time-programmed UV detection at 287 nm and 232 nm and a micellar solution of 0.17 M sodium dodecyl sulphate, 14% methanol and 0.3% triethylamine in 0.02 M phosphoric acid buffered at pH 4 as the mobile phase. The method was fully validated in accordance with ICH guidelines. The micellar method was successfully applied to quantitatively determine tylosin and josamycin residues in spiked chicken muscles, chicken liver, bovine muscles, liver, milk and eggs. It was also extended to the determination of tylosin and josamycin residues in chicken-based baby food and baby formulae. The compounds were separated by a monolithic column which, on account of its particular structure, could bear higher flow rates than usually found for this kind of analysis. High extraction efficiency for tylosin and josamycin was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. No organic solvent was used during the pretreatment step. Hence, it is considered an interesting technique for “green” chemistry. Conclusion The proposed method was validated and successfully applied for the determination of tylosin and josamycin residues in spiked chicken muscles, chicken liver, bovine muscles, liver, milk and eggs. It was also extended to the determination of tylosin and josamycin residues in chicken-based baby food and baby formulae. PMID:24976860

  12. Determination of alkylphenols in water samples using liquid chromatography-tandem mass spectrometry after pre-column derivatization with dansyl chloride.

    PubMed

    Pernica, Marek; Poloucká, Petra; Seifertová, Marta; Šimek, Zdeněk

    2015-10-23

    The present study describes an effect of reaction condition of pre-column derivatization of alkylphenols (APs): bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), and isomers of 4-nonylphenol (iso-NP) with 5-(dimethylamino) naphthalene-1-sulfonyl chloride (dansyl chloride, DNSC) on their LC-ESI-MS/MS determination in water samples. Chemical derivatization improves the sensitivity and selectivity of LC-MS/MS analysis. In principle, alkylphenols can be analyzed by LC-MS/MS without derivatization. However, pre-column derivatization of APs increases the sensitivity up to 1000 times in comparison with the analysis of underivatized alkylphenols. Reaction conditions affecting formation of the DNSC-derivatives, such as various solvent, reaction temperature, reaction time, DNSC concentration and pH values were tested. The most suitable conditions, in terms of achieving a high sensitivity, resulting from this study are: acetonitrile as reaction solvent, 60 min as reaction time, 60 °C as reaction temperature, pH values 10.5, 0.5 mg mL(-1) as DNSC concentration. Calibration curves are linear at least in the range of 1-1000 ng mL(-1), limits of detection (LOD) and limits of quantification (LOQ) ranging from 0.02 to 0.25 pg/injection and from 0.08 to 0.83 pg/injection, respectively. The improved procedure was successfully applied for the analysis of APs and BPA in real water samples. The median concentration of BPA and iso-NP obtained in bottled waters was 4.7 ng L(-1) and 33.5 ng L(-1), respectively. The median concentration of 4-t-OP was 1.3 ng L(-1.)

  13. Determination of alkylphenols in water samples using liquid chromatography-tandem mass spectrometry after pre-column derivatization with dansyl chloride.

    PubMed

    Pernica, Marek; Poloucká, Petra; Seifertová, Marta; Šimek, Zdeněk

    2015-10-23

    The present study describes an effect of reaction condition of pre-column derivatization of alkylphenols (APs): bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), and isomers of 4-nonylphenol (iso-NP) with 5-(dimethylamino) naphthalene-1-sulfonyl chloride (dansyl chloride, DNSC) on their LC-ESI-MS/MS determination in water samples. Chemical derivatization improves the sensitivity and selectivity of LC-MS/MS analysis. In principle, alkylphenols can be analyzed by LC-MS/MS without derivatization. However, pre-column derivatization of APs increases the sensitivity up to 1000 times in comparison with the analysis of underivatized alkylphenols. Reaction conditions affecting formation of the DNSC-derivatives, such as various solvent, reaction temperature, reaction time, DNSC concentration and pH values were tested. The most suitable conditions, in terms of achieving a high sensitivity, resulting from this study are: acetonitrile as reaction solvent, 60 min as reaction time, 60 °C as reaction temperature, pH values 10.5, 0.5 mg mL(-1) as DNSC concentration. Calibration curves are linear at least in the range of 1-1000 ng mL(-1), limits of detection (LOD) and limits of quantification (LOQ) ranging from 0.02 to 0.25 pg/injection and from 0.08 to 0.83 pg/injection, respectively. The improved procedure was successfully applied for the analysis of APs and BPA in real water samples. The median concentration of BPA and iso-NP obtained in bottled waters was 4.7 ng L(-1) and 33.5 ng L(-1), respectively. The median concentration of 4-t-OP was 1.3 ng L(-1.) PMID:26381567

  14. A sensitive and selective quantification of catecholamine neurotransmitters in rat microdialysates by pre-column dansyl chloride derivatization using liquid chromatography-tandem mass spectrometry.

    PubMed

    Nirogi, Ramakrishna; Komarneni, Prashanth; Kandikere, Vishwottam; Boggavarapu, Rajeshkumar; Bhyrapuneni, Gopinadh; Benade, Vijay; Gorentla, Srinivasarao

    2013-01-15

    A rapid and sensitive liquid chromatography tandem mass spectrometry method for simultaneous quantification of catecholamine neurotransmitters in microdialysates was developed. The catecholamine neurotransmitters dopamine (DA) and norepinephrine (NE) were pre-column derivatized with dansyl chloride and analyzed. A gradient elution method was used to separate the analytes from the interferences on an Agilent Poroshell 120 EC-C18 outer porous micro particulate column. The method was robust and sensitive to determine with the lower limit of quantification value of 0.068pmol/mL and 0.059pmol/mL for DA and NE, respectively. It has acceptable precision and accuracy for concentrations over the standard curve range. The method was successfully applied for simultaneous quantitation of DA and NE in the prefrontal cortex (PFC) dialysates of rats obtained from a microdialysis study dosed with vehicle and atomoxetine through intra peritoneal (i.p.) route at a dose of 3mg/kg to monitor the change in extracellular concentrations. Thus, accomplishment of this method would facilitate the neurochemical monitoring for discovery of new chemical entities targeted for the treatment of attention deficit hyperactivity disorder (ADHD). PMID:23270937

  15. Automated pre-column derivatization of thiolic fruit-antibrowning agents by sequential injection coupled to high-performance liquid chromatography using a monolithic stationary phase and an in-loop stopped-flow approach.

    PubMed

    Karakosta, Theano D; Tzanavaras, Paraskevas D; Themelis, Demetrius G

    2011-08-01

    The present study reports the very first application of ethyl propiolate (EP) as an advantageous pre-column derivatization reagent for the determination of thiols by liquid chromatography (LC). Cysteine (CYS), glutathione (GSH) and N-acetylcysteine (NAC) were derivatized online under stopped-flow conditions in a sequential injection (SI) system coupled to HPLC. The formed derivatives were separated isocratically with a monolithic stationary phase (100×4.6 mm id) and UV detected at 285 nm. Critical parameters that affected the online pre-column derivatization reaction (e.g. the reaction time and the amount concentration of EP) and the separation (e.g. pH and the composition of the mobile phase) were investigated. The developed analytical scheme offers a total analysis time of less than 10 min, limits of detection in the range of 0.24-0.35 μmol/L and satisfactory linearity up to 200 μmol/L for all analytes. The proposed method was applied to the analysis of the selected thiols--that are often employed as antibrowning agents--in fresh fruit samples.

  16. Preparation and characterization of poly(triallyl isocyanurate-co-trimethylolpropane triacrylate) monolith and its applications in the separation of small molecules by liquid chromatography.

    PubMed

    Zhong, Jing; Hao, Mengbei; Li, Ruo; Bai, Ligai; Yang, Gengliang

    2014-03-14

    A new polymeric monolith was prepared in stainless-steel column and fused-silica capillary, respectively, by atom transfer radical polymerization technique. In the polymerization, triallyl isocyanurate (TAIC) was used as the functional monomer; trimethylolpropane triacrylate (TMPTA) as the crosslinking agent; polyethylene glycol 200 and 1,2-propanediol as the co-porogens; carbon tetrachloride as the initiator and ferrous chloride as the catalyst. The conditions of polymerization were optimized. Morphology of the prepared poly(TAIC-co-TMPTA) monolith was investigated by scanning electron microscopy; pore properties were assayed by mercury porosimetry and nitrogen adsorption. The characterization indicated that the prepared reversed-phase monolith possessed uniform structure, good permeability and mechanical stability. The column was used as the stationary phase of reversed phase high performance liquid chromatography (RP-HPLC) and capillary liquid chromatography (CLC) to separate the mixture of aromatic compounds. The new column performed around 125,000 theoretical plates per meter. The column showed good reproducibility: the relative standard deviation values of the retention factor values for aromatic compounds were less than 1.52% (n=7, column-to-column).

  17. Preparation and characterization of poly(triallyl isocyanurate-co-trimethylolpropane triacrylate) monolith and its applications in the separation of small molecules by liquid chromatography.

    PubMed

    Zhong, Jing; Hao, Mengbei; Li, Ruo; Bai, Ligai; Yang, Gengliang

    2014-03-14

    A new polymeric monolith was prepared in stainless-steel column and fused-silica capillary, respectively, by atom transfer radical polymerization technique. In the polymerization, triallyl isocyanurate (TAIC) was used as the functional monomer; trimethylolpropane triacrylate (TMPTA) as the crosslinking agent; polyethylene glycol 200 and 1,2-propanediol as the co-porogens; carbon tetrachloride as the initiator and ferrous chloride as the catalyst. The conditions of polymerization were optimized. Morphology of the prepared poly(TAIC-co-TMPTA) monolith was investigated by scanning electron microscopy; pore properties were assayed by mercury porosimetry and nitrogen adsorption. The characterization indicated that the prepared reversed-phase monolith possessed uniform structure, good permeability and mechanical stability. The column was used as the stationary phase of reversed phase high performance liquid chromatography (RP-HPLC) and capillary liquid chromatography (CLC) to separate the mixture of aromatic compounds. The new column performed around 125,000 theoretical plates per meter. The column showed good reproducibility: the relative standard deviation values of the retention factor values for aromatic compounds were less than 1.52% (n=7, column-to-column). PMID:24556171

  18. Preparation of polyhedral oligomeric silsesquioxane based imprinted monolith.

    PubMed

    Li, Fang; Chen, Xiu-Xiu; Huang, Yan-Ping; Liu, Zhao-Sheng

    2015-12-18

    Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic column with high porosity and good permeability. The imprinted monolithic column was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), naproxon (template), 4-vinylpyridine, and ethylene glycol dimethacrylate, in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4). The influence of synthesis parameters on the retention factor and imprinting effect, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest imprinting factor on the imprinted monolithic column prepared with MA 0702 was 22, about 10 times higher than that prepared in absence of POSS. The comparisons between MIP monoliths synthesized with POSS and without POSS were made in terms of permeability, column efficiency, surface morphology and pore size distribution. In addition, thermodynamic and Van Deemter analysis were used to evaluate the POSS-based MIP monolith.

  19. Polymer monoliths synthesized by radiation co-polymerization in solution

    NASA Astrophysics Data System (ADS)

    Beiler, Barbara; Sáfrány, Ágnes

    2007-08-01

    Hydrophilic co-polymer monoliths were prepared by irradiating alcoholic solutions containing diethyleneglycol dimethacrylate (DEGDMA) and 2-hydroxyethylacrylate (HEA) monomers. The effect of monomer ratio, solvent properties and radiation dose on the porous properties of the monoliths was studied in detail and compared to the monolith prepared from DEGDMA. Increase of the HEA content in the co-monomer mixture (up to 18 vol%) resulted in monoliths with increased pore size and hydrophilic character. The biggest pores were obtained when methanol was used as solvent. The use of the monoliths as chromatographic columns for separation of proteins, amino and nucleic acids is also reported.

  20. Development and characterization of methacrylate-based hydrazide monoliths for oriented immobilization of antibodies.

    PubMed

    Brne, P; Lim, Y-P; Podgornik, A; Barut, M; Pihlar, B; Strancar, A

    2009-03-27

    Convective interaction media (CIM; BIA Separations) monoliths are attractive stationary phases for use in affinity chromatography because they enable fast affinity binding, which is a consequence of convectively enhanced mass transport. This work focuses on the development of novel CIM hydrazide (HZ) monoliths for the oriented immobilization of antibodies. Adipic acid dihydrazide (AADH) was covalently bound to CIM epoxy monoliths to gain hydrazide groups on the monolith surface. Two different antibodies were afterwards immobilized to hydrazide functionalized monolithic columns and prepared columns were tested for their selectivity. One column was further tested for the dynamic binding capacity. PMID:19203754

  1. Monolithic ceramics

    NASA Technical Reports Server (NTRS)

    Herbell, Thomas P.; Sanders, William A.

    1992-01-01

    A development history and current development status evaluation are presented for SiC and Si3N4 monolithic ceramics. In the absence of widely sought improvements in these materials' toughness, and associated reliability in structural applications, uses will remain restricted to components in noncritical, nonman-rated aerospace applications such as cruise missile and drone gas turbine engine components. In such high temperature engine-section components, projected costs lie below those associated with superalloy-based short-life/expendable engines. Advancements are required in processing technology for the sake of fewer and smaller microstructural flaws.

  2. Effect of hypercrosslinking conditions on pore size distribution and efficiency of monolithic stationary phases.

    PubMed

    Urban, Jiří; Škeříková, Veronika

    2014-11-01

    Three dihalogenic solvents differing in the length of alkyl chain (1,2-dichloroethane, 1,4-dichlorobutane, and 1,6-dichlorohexane) with three Friedel-Crafts alkylation catalysts varying in reactivity (AlCl3 , FeCl3 , and SnCl4 ) have been used to prepare hypercrosslinked poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) columns. Hydrodynamic characteristics as well as column efficiency and mass transfer resistance were tuned by the combination of swelling solvent and alkylation reaction catalyst in the modification mixture. The column swelled in 1,6-dichlorohexane and hypercrosslinked in the presence of AlCl3 provided the highest column efficiency and enabled fast isocratic separations of small molecules in a RP mode. To uncover factors controlling the efficiency of hypercrosslinked monolithic columns, we have studied pore volume distribution of prepared columns. We found that column efficiency increases with the higher pore volume of pores smaller than 2 nm. PMID:25113521

  3. Comparison of perfusion media and monoliths for protein and virus-like particle chromatography.

    PubMed

    Wu, Yige; Abraham, Dicky; Carta, Giorgio

    2016-05-20

    Structural and performance characteristics of perfusion chromatography media (POROS HS 20 and 50) and those of a polymethacrylate monolith (CIM SO3-1 tube monolith column) are compared for protein and virus-like particle chromatography using 1mL columns. Axial flow columns are used for POROS while the monolith has a radial flow configuration, which provides comparable operating pressures. The POROS beads contain a bimodal distribution of pore sizes, some as large as 0.5μm, which allow a small fraction of the mobile phase to flow within the particles, while the monolith contains 1-2μm flow channels. For proteins (lysozyme and IgG), the dynamic binding capacity of the POROS columns is more than twice that of the monolith at longer residence times. While the DBC of the POROS HS 50 column decreases at shorter residence times, the DBC of the POROS HS 20 column for IgG remains nearly twice that of the monolith at residence times at least as low as 0.2min as a result of intraparticle convection. Protein recoveries are comparable for all three columns. For VLPs, however, the eluted peaks are broader and recovery is lower for the monolith than for the POROS columns and is dependent on the direction of flow in the monolith, which is attributed to denser layer observed by SEM at the inlet surface of the monolith that appears to trap VLPs when loading in the normal flow direction. PMID:27106397

  4. Less common applications of monoliths: Preconcentration andsolid-phase extraction

    SciTech Connect

    Svec, Frantisek

    2006-03-27

    Monolithic materials are finding their place in a variety of fields. While liquid chromatography is the most emphasized use of this new category of porous media, some other just as important applications are eclipsed by the success of monolithic columns. This review article describes all current facets of use of monoliths in preconcentration and solid-phase extraction. In addition to the typical off line use that does not seem to be the main stream application for the monolithic materials, in-line connection of the preconcentration with HPLC, electrochromatography, electrophoresis, enzymatic digestion, as well as its applications in microfluidics are presented.

  5. Development of erbium phosphate doped poly(glycidyl methacrylate/ethylene dimethacrylate) spin columns for selective enrichment of phosphopeptides.

    PubMed

    Güzel, Yüksel; Rainer, Matthias; Messner, Christoph B; Hussain, Shah; Meischl, Florian; Sasse, Michael; Tessadri, Richard; Bonn, Günther K

    2015-05-01

    In this study, a novel method for the highly selective enrichment of phosphopeptides using erbium phosphate doped poly(glycidyl methacrylate/ethylene dimethacrylate) spin columns is presented. Erbium phosphate was synthesized by precipitation from boiling phosphoric acid and incubated overnight in erbium chloride solutions. The resulting powder was embedded in a monolithic poly(glycidyl methacrylate/ethylene dimethacrylate) polymer. The monolith was synthesized in a spin column by radical polymerization. Erbium phosphate demonstrated a high affinity and selectivity for phosphopeptides due to the strong interaction of trivalent erbium ions with the phosphate groups of phosphopeptides. The high selectivity and performance of the designed spin columns were demonstrated by successfully enriching phosphopeptides from tryptically digested protein mixtures containing the model phosphoproteins α- and β-casein, bovine milk, and human saliva. By the implementation of several washing steps, unspecific components were removed and the enriched phosphopeptides were effectively eluted from the spin columns under alkaline conditions. The selective performance of the presented method was further demonstrated by the enrichment of two synthetic phosphopeptides, which were spiked in tryptically digested and dephosphorylated HeLa cell lysates at low ratios. Finally, the presented approach was compared to conventional phosphopeptide enrichment by titanium oxide and revealed higher recoveries for the erbium phosphate doped monoliths.

  6. Surface modified aerogel monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

    2013-01-01

    This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

  7. Methacrylate monolith chromatography as a tool for waterborne virus removal.

    PubMed

    Rački, N; Kramberger, P; Steyer, A; Gašperšič, J; Štrancar, A; Ravnikar, M; Gutierrez-Aguirre, I

    2015-02-13

    Enteric viruses are commonly present in environmental waters and represent the major cause of waterborne infections and outbreaks. Since traditional wastewater treatments fail to remove enteric viruses in the water purification process, they are released daily into environmental waters. Monolithic supports have enabled chromatography to enter the field of virology. They have been successfully used in virus purification and concentration. In this work quaternary amine (QA) methacrylate monoliths were exploited to remove enteric viruses from wastewater treatment plant effluent. Expectedly, chromatographic processing of such a complex medium was troublesome, even for monoliths, characterized by extremely large pore dimensions. This problem was solved by introducing a pre-step chromatography using hydroxyl (OH) methacrylate monoliths. This way, molecules, that would hinder virus binding to the anion-exchanger monolith, were removed. As a result, the OH pre-column reduced backpressure increase on the subsequent anion-exchanger column, and increased both QA column binding capacity and life time. Wastewater effluent samples were successfully purified from five waterborne enteric viruses (rotavirus, norovirus genogroup I and II, astrovirus, sapovirus), below the detection limit of RT-qPCR. The breakthrough of the rotavirus binding capacity was not reached for concentrations that significantly exceeded those expected in effluent waters. The obtained results confirm that methacrylate monoliths can be a valuable tool for simultaneous removal of different waterborne viruses from contaminated water sources.

  8. Monolithic exploding foil initiator

    DOEpatents

    Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

    2012-10-23

    A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

  9. New Monolithic Dome Schools.

    ERIC Educational Resources Information Center

    Parker, Freda

    2000-01-01

    Discusses how the Grand Meadow (Minnesota) school district got more than twice the grant money asked for from the state's legislature as well as voter approval for five new $8 million monolithic domes for their K-12 facility. Three additional school district successes in developing monolithic domes for their schools are examined. (GR)

  10. Fabrication and characterization of aligned macroporous monolith for high-performance protein chromatography.

    PubMed

    Du, Kaifeng; Zhang, Qi; Dan, Shunmin; Yang, Min; Zhang, Yongkui; Chai, Dezhi

    2016-04-22

    In the present study, a freeze casting method combined with particle accumulation was applied to fabricate the aligned macroporous monolith for high-performance protein chromatography. For the preparation, the reactive colloids were first prepared by using glycidyl methacrylate and ethylene glycol dimethacrylate as monomers. Subsequently, these colloids accumulated regularly and polymerized into the aligned macroporous monolith. The aligned porous structure of the monolith was characterized by SEM, mercury intrusion, and flow hydrodynamics. The results revealed that the generated monolith was possessed of aligned macropores in size of about 10 μm and high column permeability. Finally, after being modified with sulfonated groups, the monolith was evaluated for its chromatographic performance. It demonstrated that the aligned macropores endowed the monolith with excellent adsorption capacity and high column efficiency. PMID:27016114

  11. Fabrication and characterization of aligned macroporous monolith for high-performance protein chromatography.

    PubMed

    Du, Kaifeng; Zhang, Qi; Dan, Shunmin; Yang, Min; Zhang, Yongkui; Chai, Dezhi

    2016-04-22

    In the present study, a freeze casting method combined with particle accumulation was applied to fabricate the aligned macroporous monolith for high-performance protein chromatography. For the preparation, the reactive colloids were first prepared by using glycidyl methacrylate and ethylene glycol dimethacrylate as monomers. Subsequently, these colloids accumulated regularly and polymerized into the aligned macroporous monolith. The aligned porous structure of the monolith was characterized by SEM, mercury intrusion, and flow hydrodynamics. The results revealed that the generated monolith was possessed of aligned macropores in size of about 10 μm and high column permeability. Finally, after being modified with sulfonated groups, the monolith was evaluated for its chromatographic performance. It demonstrated that the aligned macropores endowed the monolith with excellent adsorption capacity and high column efficiency.

  12. Titanium-scaffolded organic-monolithic stationary phases for ultra-high-pressure liquid chromatography.

    PubMed

    Vonk, Rudy J; Vaast, Axel; Eeltink, Sebastiaan; Schoenmakers, Peter J

    2014-09-12

    Organic-polymer monoliths with overall dimensions larger than one millimetre are prone to rupture - either within the monolith itself or between the monoliths and the containing wall - due to the inevitable shrinkage accompanying the formation of a cross-linked polymeric network. This problem has been addressed by creating titanium-scaffolded poly(styrene-co-divinylbenzene) (S-co-DVB) monoliths. Titanium-scaffolded monoliths were successfully used in liquid chromatography at very high pressures (up to 80MPa) and using gradients spanning the full range of water-acetonitrile compositions (0 to 100%). The kinetic-performance of (50-mm long) titanium-scaffolded monoliths was compared to that of similar monolith created in 1-mm i.d. glass-lined tubing at pressures up to 50MPa. The peak capacities obtained with the titanium-scaffolded column was about 30% lower. An increased Eddy-diffusion, due to the pillar-structure, and a decreased permeability are thought to be the main reasons for this reduced kinetic-performance. No decrease in performance was observed when the titanium-scaffolded columns were operated at pressures of 80MPa for up to 12h. The column-to-column repeatability (n=5) was acceptable in terms of observed peak widths at half heights (RSD ca. 10%) The run-to-run repeatability (n=135) in terms of retention times and peak widths at half height were found to be good. Titanium-scaffolded columns coupled in series up to a combined length of (200mm) were used for the analyses of a complex Escherichia coli protein sample. Our experiments demonstrate that columns based on titanium-scaffolded organic-polymer monolith can be operated under strenuous conditions without loss in performance. The titanium-scaffolded approach makes it feasible to create organic-polymer monoliths in wide-bore columns with accurate temperature control.

  13. Phenylalanine functionalized zwitterionic monolith for hydrophobic interaction electrochromatography.

    PubMed

    Wang, Jiabin; Jia, Wenchao; Lin, Xucong; Wu, Xiaoping; Xie, Zenghong

    2013-12-01

    A novel phenylalanine (Phe) functionalized zwitterionic monolith for hydrophobic electrochromatography was prepared by a two-step procedure involving the synthesis of glycidyl methacrylate based polymer monolith and subsequent on-column chemical modification with Phe via ring-opening reaction of epoxides. Benefitting from the hydrophobicity of both methacrylate-based matrix and aromatic group of Phe, this monolith could exhibit good hydrophobic interaction for the separation. Typical RP chromatographic behavior was observed toward various solutes. The well-controlled cathodic or anodic EOF of the prepared column could be facilely switched by altering the pH values of running buffers. The separation mechanism of this Phe functionalized zwitterionic monolith is discussed in detail. Two mixed-mode mechanisms of RP/cation exchange and RP/anion exchange could be further realized on the same monolith in different pH condition of the mobile phase. Versatile separation capabilities of neutral, basic, and acidic analytes have been successfully achieved in this zwitterionic monolith by CEC method.

  14. Vinylbenzyl quaternary ammonium-based polymeric monolith with hydrophilic interaction/strong anion exchange mixed-mode for pressurized capillary electrochromatography.

    PubMed

    Lin, Xucong; Feng, Shuhui; Jia, Wenchao; Ding, Kang; Xie, Zenghong

    2013-11-01

    A novel polymeric monolith with hydrophilic interaction and strong anion-exchange mixed-mode has been fabricated for pressurized capillary electrochromatography by an in situ copolymerization of vinylbenzyl trimethylammonium chloride (VBTA) and bisphenol A glycerolate dimethacrylate (BisGMA). The optimization of the polymerization mixture composition has been investigated, and column characteristics in terms of mechanical stability, permeability and reproducibility have been studied in detail. Linear responses between back pressure and flow rate have been achieved in different solvents. The absolute value of swelling propensity (SP) factor for poly(VBTA-co-BisGMA) monolith is 0.41, and the degree of permeability drop from pure ACN to water is about 45%. An acceptable mechanical stability of the column is obtained. The suitable reproducibility is also measured with the RSD for day-to-day (n=3) of retention time and column efficiency less than 3.3%, and the RSD for batch-to-batch (n=3) less than 5.3%, respectively. Under the optimum conditions, the mixed-mode of hydrophilic interaction and strong anion-exchange has been carried out, and efficient electrochromatography profiling of various polar compounds including neutral phenols, negatively charged benzoic acids and positively charged nucleic acid bases and nucleosides are achieved, respectively. PMID:24125728

  15. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    PubMed

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar).

  16. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    PubMed

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar). PMID:25622518

  17. Purification of infective baculoviruses by monoliths.

    PubMed

    Gerster, Petra; Kopecky, Eva-Maria; Hammerschmidt, Nikolaus; Klausberger, Miriam; Krammer, Florian; Grabherr, Reingard; Mersich, Christa; Urbas, Lidija; Kramberger, Petra; Paril, Tina; Schreiner, Matthias; Nöbauer, Katharina; Razzazi-Fazeli, Ebrahim; Jungbauer, Alois

    2013-05-17

    A chromatographic process based on monoliths for purification of infective baculovirus without prior concentration step has been established. Baculovirus produced in Spodoptera frugiperda cells (Sf-9) were harvested by centrifugation, filtered through 0.8 μm filters and directly loaded onto radial 1 mL anion exchange monoliths with a channel size of 1.5-2.0 μm operated at a volumetric flow rate of one bed volume per minute. Optional an epoxy monolith was used as pre-column to reduce interfering compounds and substances influencing the capacity of anion exchange monoliths for baculovirus infectious virus could be eluted with a step gradient at salt concentrations of 440 mM NaCl. Recovery of infectious virus was highly influenced by composition and age of supernatant and ranged from 20 to >99% active baculovirus. Total protein content could be reduced to 1-8% and DNA content to 38-48% in main virus fraction. Infective virus could be 52-fold concentrated within 20.5h and simultaneously an 82-fold volume reduction was possible when loading 1150 mL (2.1×10(8) pfu/mL) onto 1 mL scale support.

  18. Thermoresponsive ketoprofen-imprinted monolith prepared in ionic liquid.

    PubMed

    Sun, Xuan; Zhao, Chun-Yan; Wang, Xian-Hua; Huang, Yan-Ping; Liu, Zhao-Sheng

    2014-09-01

    A thermoresponsive imprinted monolith with the ability of molecular recognition for ketoprofen was prepared for the first time. The smart monolith was synthesized in a stainless steel column using acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) as functional monomers, which can form interpolymer complexation to restrict access of the analyte to the imprinted networks at low temperatures. To avoid a high back pressure of the column derived from neat dimethyl sulfoxide (DMSO) as a porogenic solvent that is needed to solve polar AMPS, an ionic liquid, [BMIM]BF4, was introduced into the pre-polymerization mixture. The molecular recognition ability towards ketoprofen of the resulting thermoresponsive molecularly imprinted polymer (MIP) monolith displayed significant dependence on temperature compared with a non-imprinted column (NIP), and the greatest imprinting factor was achieved at the transition temperature of 35 °C (above 10). Furthermore, the number of binding sites of the smart MIP monolith at 35 °C was about 76 times as large as that at 25 °C. In addition, Freundlich analyses indicated that the thermoresponsive MIP monolith had homogeneous affinity sites at both 25 and 35 °C with heterogeneity index 0.9251 and 0.9851, respectively.

  19. Preparation of polyhedral oligomeric silsesquioxane-based hybrid monolith by ring-opening polymerization and post-functionalization via thiol-ene click reaction.

    PubMed

    Liu, Zhongshan; Ou, Junjie; Lin, Hui; Wang, Hongwei; Dong, Jing; Zou, Hanfa

    2014-05-16

    A polyhedral oligomeric silsesquioxane (POSS) hybrid monolith was simply prepared by using octaglycidyldimethylsilyl POSS (POSS-epoxy) and cystamine dihydrochloride as monomers via ring-opening polymerization. The effects of composition of prepolymerization solution and polycondensation temperature on the morphology and permeability of monolithic column were investigated in detail. The obtained POSS hybrid monolithic column showed 3D skeleton morphology and exhibited high column efficiency of ∼71,000 plates per meter in reversed-phase mechanism. Owing to this POSS hybrid monolith essentially possessing a great number of disulfide bonds, the monolith surface would expose thiol groups after reduction with dithiothreitol (DTT), which supplied active sites to functionalize with various alkene monomers via thiol-ene click reaction. The results indicated that the reduction with DTT could not destroy the 3D skeleton of hybrid monolith. Both stearyl methylacrylate (SMA) and benzyl methacrylate (BMA) were selected to functionalize the hybrid monolithic columns for reversed-phase liquid chromatography (RPLC), while [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl)-ammonium hydroxide (MSA) was used to modify the hybrid monolithic column in hydrophilic interaction chromatography (HILIC). These modified hybrid monolithic columns could be successfully applied for separation of small molecules with high efficiency. It is demonstrated that thiol-ene click reaction supplies a facile way to introduce various functional groups to the hybrid monolith possessing thiol groups. Furthermore, due to good permeability of the resulting hybrid monoliths, we also prepared long hybrid monolithic columns in narrow-bore capillaries. The highest column efficiency reached to ∼70,000 plates using a 1-m-long column of 75μm i.d. with a peak capacity of 147 for isocratic chromatography, indicating potential application in separation and analysis of complex biosamples.

  20. Pepsin immobilization on an aldehyde-modified polymethacrylate monolith and its application for protein analysis.

    PubMed

    Han, Wenjuan; Yamauchi, Mika; Hasegawa, Urara; Noda, Masanori; Fukui, Kiichi; van der Vlies, André J; Uchiyama, Susumu; Uyama, Hiroshi

    2015-05-01

    Polymer-based monoliths with interconnected porous structure have attracted much attention as a high-performance stationary phase for online digestion liquid chromatography-mass spectrometry (LC-MS) system. In this study, a poly(glycidyl methacrylate-co-methyl methacrylate) (PGM) monolith prepared via thermally induced phase separation (TIPS) was used as a solid support to covalently immobilize pepsin. The PGM monolith was modified with aminoacetal to yield an aldehyde-bearing (PGM-CHO) monolith. Pepsin was immobilized onto the PGM-CHO monolith via reductive amination. The immobilized pepsin showed better pH and thermal stability compared with free pepsin. Furthermore, the PGM-CHO monolith modified with pepsin was applied for online protein digestion followed by LC-MS and LC-MS/MS analyses. As a result, a larger number of peptides are reproducibly identified compared to those by polystyrene/divinylbenzene particle (POROS)-based online pepsin column.

  1. Incorporation of graphene oxide nanosheets into boronate-functionalized polymeric monolith to enhance the electrochromatographic separation of small molecules.

    PubMed

    Lin, Zian; Wang, Juan; Yu, Ruifang; Yin, Xiaofei; He, Yu

    2015-02-01

    Graphene oxide (GO) nanosheets were incorporated into an organic polymer monolith containing 3-acrylamidophenylboronic acid (AAPBA) and pentaerythritol triacrylate (PETA) to form a novel monolithic stationary phase for CEC. The effects of the mass ratio of AAPBA/PETA, the amount of GO, and the volume of porogen on the morphology, permeability and pore properties of the prepared poly(AAPBA-GO-PETA) monoliths were investigated. A series of test compounds including amides, alkylbenzenes, polycyclic aromatics, phenols, and anilines were used to evaluate and compare the separation performances of the poly(AAPBA-GO-PETA) and the parent poly(AAPBA-co-PETA) monoliths. The results indicated that incorporation of GO into monolithic column exhibited much higher resolutions (>1.5) and column efficiency (62,000 ∼ 110,000 plates/m for toluene, DMF, formamide, and thiourea) than the poly(AAPBA-co-PETA). The successful application in isocratic separation of peptides suggests the potential of the GO incorporated monolithic column in complex sample analysis. In addition, the reproducibility and stability of the prepared poly(AAPBA-GO-PETA) monolith was assessed. The run-to-run, column-to-column and batch-to-batch reproducibilities of this monolith for alkylbenzenes' retention were satisfactory with the RSDs less than 1.8% (n = 5), 3.7% and 5.6% (n = 3), respectively, indicating the effectiveness and practicability of the proposed method.

  2. Incorporation of graphene oxide nanosheets into boronate-functionalized polymeric monolith to enhance the electrochromatographic separation of small molecules.

    PubMed

    Lin, Zian; Wang, Juan; Yu, Ruifang; Yin, Xiaofei; He, Yu

    2015-02-01

    Graphene oxide (GO) nanosheets were incorporated into an organic polymer monolith containing 3-acrylamidophenylboronic acid (AAPBA) and pentaerythritol triacrylate (PETA) to form a novel monolithic stationary phase for CEC. The effects of the mass ratio of AAPBA/PETA, the amount of GO, and the volume of porogen on the morphology, permeability and pore properties of the prepared poly(AAPBA-GO-PETA) monoliths were investigated. A series of test compounds including amides, alkylbenzenes, polycyclic aromatics, phenols, and anilines were used to evaluate and compare the separation performances of the poly(AAPBA-GO-PETA) and the parent poly(AAPBA-co-PETA) monoliths. The results indicated that incorporation of GO into monolithic column exhibited much higher resolutions (>1.5) and column efficiency (62,000 ∼ 110,000 plates/m for toluene, DMF, formamide, and thiourea) than the poly(AAPBA-co-PETA). The successful application in isocratic separation of peptides suggests the potential of the GO incorporated monolithic column in complex sample analysis. In addition, the reproducibility and stability of the prepared poly(AAPBA-GO-PETA) monolith was assessed. The run-to-run, column-to-column and batch-to-batch reproducibilities of this monolith for alkylbenzenes' retention were satisfactory with the RSDs less than 1.8% (n = 5), 3.7% and 5.6% (n = 3), respectively, indicating the effectiveness and practicability of the proposed method. PMID:25395232

  3. Monolithic microwave integrated circuits

    NASA Astrophysics Data System (ADS)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  4. Pore volume accessibility of particulate and monolithic stationary phases.

    PubMed

    Urban, Jiří

    2015-05-29

    A chromatographic characterization of pore volume accessibility for both particulate and monolithic stationary phases is presented. Size-exclusion calibration curves have been used to determine the pore volume fraction that is accessible for six alkylbenzenes and twelve polystyrene standards in tetrahydrofuran as the mobile phase. Accessible porosity has been then correlated with the size of the pores from which individual compounds are just excluded. I have determined pore volume accessibility of commercially available columns packed with fully and superficially porous particles, as well as with silica-based monolithic stationary phase. I also have investigated pore accessibility of polymer-based monolithic stationary phases. Suggested protocol is used to characterize pore formation at the early stage of the polymerization, to evaluate an extent of hypercrosslinking during modification of pore surface, and to characterize the pore accessibility of monolithic stationary phases hypercrosslinked after an early termination of polymerization reaction. Pore volume accessibility was also correlated to column efficiency of both particulate and monolithic stationary phases. PMID:25892635

  5. Spatial and temporal distribution of the leaching of surface applied tracers from an irrigated monolith of a loamy vineyard soil.

    PubMed

    Bloem, E; Hermon, K M; de Rooij, G H; Stagnitti, F

    2014-01-01

    Fresh water scarcity is an increasing problem worldwide. Strategies to alleviate water scarcity include the use of low-quality water for irrigation. The risk of groundwater contamination by pollutants in this water is affected by soil heterogeneity and preferential flow. These risk factors can be assessed by measuring the spatio-temporal redistribution of uniformly applied water and solutes. We placed a soil monolith (height 29 cm) from an Australian vineyard on a 100-cell multi-compartment sampler (MCS). At this vineyard, treated wastewater is used in response to the severe shortage of water in the summer. We studied the leaching risk associated with heterogeneous or preferential flow by irrigating the soil column with 24 applications to simulate one year. We applied simulated rainfall as well as wastewater (which contained chloride) during summer while relying on rainfall only in winter. We compared the chloride leaching with the leaching of bromide, which was applied during one of the applications as a pulse. During the entire simulated year, leaching of solutes from the monolith was measured. The results indicate that the assumption of uniform flow would underestimate the risk for the fresh groundwater reserves: 25% of the solutes are transported though 6% of the soil's cross-section. The spatial distribution of drainage and solute leaching varied little during the experiment. Consequently, the mass flux density pattern of the bromide pulse was comparable to that of the repeatedly applied chloride. However, the MCS data suggested lateral 'escape' from chloride to non-mobile areas, which means in the long run, considerable quantities of these solutes can build up in areas that do not receive irrigation water.

  6. Spatial and temporal distribution of the leaching of surface applied tracers from an irrigated monolith of a loamy vineyard soil.

    PubMed

    Bloem, E; Hermon, K M; de Rooij, G H; Stagnitti, F

    2014-01-01

    Fresh water scarcity is an increasing problem worldwide. Strategies to alleviate water scarcity include the use of low-quality water for irrigation. The risk of groundwater contamination by pollutants in this water is affected by soil heterogeneity and preferential flow. These risk factors can be assessed by measuring the spatio-temporal redistribution of uniformly applied water and solutes. We placed a soil monolith (height 29 cm) from an Australian vineyard on a 100-cell multi-compartment sampler (MCS). At this vineyard, treated wastewater is used in response to the severe shortage of water in the summer. We studied the leaching risk associated with heterogeneous or preferential flow by irrigating the soil column with 24 applications to simulate one year. We applied simulated rainfall as well as wastewater (which contained chloride) during summer while relying on rainfall only in winter. We compared the chloride leaching with the leaching of bromide, which was applied during one of the applications as a pulse. During the entire simulated year, leaching of solutes from the monolith was measured. The results indicate that the assumption of uniform flow would underestimate the risk for the fresh groundwater reserves: 25% of the solutes are transported though 6% of the soil's cross-section. The spatial distribution of drainage and solute leaching varied little during the experiment. Consequently, the mass flux density pattern of the bromide pulse was comparable to that of the repeatedly applied chloride. However, the MCS data suggested lateral 'escape' from chloride to non-mobile areas, which means in the long run, considerable quantities of these solutes can build up in areas that do not receive irrigation water. PMID:24638830

  7. Embedded-monolith armor

    DOEpatents

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  8. Fabrication of large-sized silica monolith exceeding 1000 mL with high structural homogeneity.

    PubMed

    Miyamoto, Riichi; Ando, Yukiko; Kurusu, Chie; Bai, Hong-zhi; Nakanishi, Kazuki; Ippommatsu, Masamichi

    2013-06-01

    Reproducible fabrication of the hierarchically porous monolithic silica in a large volume exceeding 1000 mL has been established. By the hydrothermal enlargement of the fully accessible small pores to exceed 50 nm in diameter, the capillary force emerged on solvent evaporation was dramatically reduced, which allowed the preparation of crack-free monoliths with evaporative solvent removal under an ambient pressure. The local temperature inhomogeneity within a reaction vessel in a large volume was precisely controlled to cancel the heat evolved by the hydrolysis reaction of tetramethoxysilane and that consumed to melt ice cubes dispersed in the solution, resulting in large monolithic silica pieces with improved structural homogeneity. Homogeneity of the pore structure was confirmed, both on macro- and mesoscales, using SEM, mercury intrusion, and nitrogen adsorption/desorption measurements. Furthermore, the deviations in chromatographic performance were examined by evaluating multiple smaller monolithic columns prepared from the monolithic silica pieces cut from different parts of a large monolith. All the daughter columns thus prepared exhibited comparable performances to each other to prove the overall homogeneity of the mother monolith. Preliminary results on high-speed separation of peptides and proteins by the octadecylsilylated silica monolith of the above production have also been demonstrated. PMID:23568889

  9. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    PubMed

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-01

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach.

  10. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    PubMed

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-01

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach. PMID:23434082

  11. Chloride Test

    MedlinePlus

    ... Addison disease, or increased salt intake. If both chloride and sodium levels are high in a person on a ... anything else I should know? Drugs that affect sodium blood levels will also cause changes in chloride. In addition, swallowing large amounts of baking soda ...

  12. Silica-based polypeptide-monolithic stationary phase for hydrophilic chromatography and chiral separation.

    PubMed

    Zhao, Licong; Yang, Limin; Wang, Qiuquan

    2016-05-13

    Glutathione (GSH)-, somatostatin acetate (ST)- and ovomucoid (OV)-functionalized silica-monolithic stationary phases were designed and synthesized for HILIC and chiral separation using capillary electrochromatography (CEC). GSH, ST and OV were covalently incorporated into the silica skeleton via the epoxy ring-opening reaction between their amino groups and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS) together with polycondensation and copolymerization of tetramethyloxysilane and GPTMS. Not only could the direction and electroosmotic flow magnitude on the prepared GSH-, ST- and OV-silica hybrid monolithic stationary phases be controlled by the pH of the mobile phase, but also a typical HILIC behavior was observed so that the nucleotides and HPLC peptide standard mixture could be baseline separated using an aqueous mobile phase without any acetonitrile during CEC. Moreover, the prepared monolithic columns had a chiral separation ability to separate dl-amino acids. The OV-silica hybrid monolithic column was most effective in chiral separation and could separate dl-glutamic acid (Glu) (the resolution R=1.07), dl-tyrosine (Tyr) (1.57) and dl-histidine (His) (1.06). Importantly, the chiral separation ability of the GSH-silica hybrid monolithic column could be remarkably enhanced when using gold nanoparticles (AuNPs) to fabricate an AuNP-mediated GSH-AuNP-GSH-silica hybrid monolithic column. The R of dl-Glu, dl-Tyr and dl-His reached 1.19, 1.60 and 2.03. This monolithic column was thus applied to separate drug enantiomers, and quantitative separation of all four R/S drug enantiomers were achieved with R ranging from 4.36 to 5.64. These peptide- and protein-silica monolithic stationary phases with typical HILIC separation behavior and chiral separation ability implied their promise for the analysis of not only the future metabolic studies, but also drug enantiomers recognition.

  13. Preparation of a boronate-functionalized affinity hybrid monolith for specific capture of glycoproteins.

    PubMed

    Yang, F; Mao, J; He, X W; Chen, L X; Zhang, Y K

    2013-06-01

    A novel strategy for preparation of a boronate affinity hybrid monolith was developed using a Cu(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) reaction of an alkyne-boronate ligand with an azide-functionalized monolithic intermediate. An azide-functionalized hybrid monolith was first synthesized via a single-step procedure to provide reactive sites for click chemistry; then the alkyne-boronate ligands were covalently immobilized on the azide-functionalized hybrid monolith via an in-column CuAAC reaction to form a boronate affinity hybrid monolith under mild conditions. The boronate affinity monolith was characterized and evaluated by means of elemental analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The boronate affinity hybrid monolith exhibited excellent specificity toward nucleosides and glycoproteins, which were chosen as test cis-diol-containing compounds under neutral conditions. The binding capacity of the monolith for the glycoprotein ovalbumin was 2.36 mg · g(-1) at pH 7.0. The practicability of the boronate affinity hybrid monolithic material was demonstrated by specific capture of the glycoproteins ovalbumin and ovotransferrin from an egg sample.

  14. Monolithic MACS micro resonators

    NASA Astrophysics Data System (ADS)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  15. Monolithic MACS micro resonators.

    PubMed

    Lehmann-Horn, J A; Jacquinot, J-F; Ginefri, J C; Bonhomme, C; Sakellariou, D

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1/P is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4mm rotor at 500MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials. PMID:27544845

  16. Monolithic Optoelectronic Integrated Circuit

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Walters, Wayne; Gustafsen, Jerry; Bendett, Mark

    1990-01-01

    Monolithic optoelectronic integrated circuit (OEIC) receives single digitally modulated input light signal via optical fiber and converts it into 16-channel electrical output signal. Potentially useful in any system in which digital data must be transmitted serially at high rates, then decoded into and used in parallel format at destination. Applications include transmission and decoding of control signals to phase shifters in phased-array antennas and also communication of data between computers and peripheral equipment in local-area networks.

  17. Monolithic Millimeter Wave Oscillator

    NASA Astrophysics Data System (ADS)

    Wang, Nan-Lei

    There is an increasing interest in the millimeter -wave spectrum for use in communications and for military and scientific applications. The concept of monolithic integration aims to produce very-high-frequency circuits in a more reliable, reproducible way than conventional electronics, and also at lower cost, with smaller size and lighter weight. In this thesis, a negative resistance device is integrated monolithically with a resonator to produce an effective oscillator. This work fills the void resulting from the exclusion of the local oscillator from the monolithic millimeter-wave integrated circuit (MMMIC) receiver design. For convenience a microwave frequency model was used to design the resonator circuit. A 5 GHz hybrid oscillator was first fabricated to test the design; the necessary GaAs process technology was developed for the fabrication. Negative resistance devices and oscillator theory were studied, and a simple but practical model of the Gunn diode was devised to solve the impedance matching problem. Monolithic oscillators at the Ka band (35 GHz) were built and refined. All devices operated in CW mode. By means of an electric-field probe, the output power was coupled into a metallic waveguide for measurement purposes. The best result was 3.63 mW of power output, the highest efficiency was 0.43% and the frequency stability was better than 10-4. In the future, an IMPATT diode could replace the Gunn device to give much higher power and efficiency. A varactor-tuned circuit also suitable for large-scale integration is under study.

  18. Monolith electroplating process

    DOEpatents

    Agarrwal, Rajev R.

    2001-01-01

    An electroplating process for preparing a monolith metal layer over a polycrystalline base metal and the plated monolith product. A monolith layer has a variable thickness of one crystal. The process is typically carried in molten salts electrolytes, such as the halide salts under an inert atmosphere at an elevated temperature, and over deposition time periods and film thickness sufficient to sinter and recrystallize completely the nucleating metal particles into one single crystal or crystals having very large grains. In the process, a close-packed film of submicron particle (20) is formed on a suitable substrate at an elevated temperature. The temperature has the significance of annealing particles as they are formed, and substrates on which the particles can populate are desirable. As the packed bed thickens, the submicron particles develop necks (21) and as they merge into each other shrinkage (22) occurs. Then as micropores also close (23) by surface tension, metal density is reached and the film consists of unstable metal grain (24) that at high enough temperature recrystallize (25) and recrystallized grains grow into an annealed single crystal over the electroplating time span. While cadmium was used in the experimental work, other soft metals may be used.

  19. A novel ionic liquid-modified organic-polymer monolith as the sorbent for in-tube solid-phase microextraction of acidic food additives.

    PubMed

    Wang, Ting-Ting; Chen, Yi-Hui; Ma, Jun-Feng; Hu, Min-Jie; Li, Ying; Fang, Jiang-Hua; Gao, Hao-Qi

    2014-08-01

    A novel ionic liquid-modified organic-polymer monolithic capillary column was prepared and used for in-tube solid-phase microextraction (SPME) of acidic food additives. The primary amino group of 1-aminopropyl-3-methylimidazolium chloride was reacted with the epoxide group of glycidyl methacrylate. The as-prepared new monomer was then copolymerized in situ with acrylamide and N,N'-methylenebisacrylamide in the presence of polyethylene glycol (PEG)-8000 and PEG-10,000 as porogens. The extraction performance of the developed monolithic sorbent was evaluated for benzoic acid, 3-hydroxybenzoic acid, cinnamic acid, 2,4-dichlorophenoxyacetic acid, and 3-(trifluoromethyl)-cinnamic acid. Such a sorbent, bearing hydrophobic and anion-exchange groups, had high extraction efficiency towards the test compounds. The adsorption capacities for the analytes dissolved in water ranged from 0.18 to 1.74 μg cm(-1). Good linear calibration curves (R(2) > 0.99) were obtained, and the limits of detection (S/N = 3) for the analytes were found to be in the range 1.2-13.5 ng mL(-1). The recoveries of five acidic food additives spiked in Coca-Cola beverage samples ranged from 85.4 % to 98.3 %, with RSD less than 6.9 %. The excellent applicability of the ionic liquid (IL)-modified monolithic column was further tested by the determination of benzoic acid content in Sprite samples, further illustrating its good potential for analyzing food additives in complex samples. PMID:24939131

  20. A novel ionic liquid-modified organic-polymer monolith as the sorbent for in-tube solid-phase microextraction of acidic food additives.

    PubMed

    Wang, Ting-Ting; Chen, Yi-Hui; Ma, Jun-Feng; Hu, Min-Jie; Li, Ying; Fang, Jiang-Hua; Gao, Hao-Qi

    2014-08-01

    A novel ionic liquid-modified organic-polymer monolithic capillary column was prepared and used for in-tube solid-phase microextraction (SPME) of acidic food additives. The primary amino group of 1-aminopropyl-3-methylimidazolium chloride was reacted with the epoxide group of glycidyl methacrylate. The as-prepared new monomer was then copolymerized in situ with acrylamide and N,N'-methylenebisacrylamide in the presence of polyethylene glycol (PEG)-8000 and PEG-10,000 as porogens. The extraction performance of the developed monolithic sorbent was evaluated for benzoic acid, 3-hydroxybenzoic acid, cinnamic acid, 2,4-dichlorophenoxyacetic acid, and 3-(trifluoromethyl)-cinnamic acid. Such a sorbent, bearing hydrophobic and anion-exchange groups, had high extraction efficiency towards the test compounds. The adsorption capacities for the analytes dissolved in water ranged from 0.18 to 1.74 μg cm(-1). Good linear calibration curves (R(2) > 0.99) were obtained, and the limits of detection (S/N = 3) for the analytes were found to be in the range 1.2-13.5 ng mL(-1). The recoveries of five acidic food additives spiked in Coca-Cola beverage samples ranged from 85.4 % to 98.3 %, with RSD less than 6.9 %. The excellent applicability of the ionic liquid (IL)-modified monolithic column was further tested by the determination of benzoic acid content in Sprite samples, further illustrating its good potential for analyzing food additives in complex samples.

  1. One-pot synthesis of a new high vinyl content hybrid silica monolith dedicated to nanoliquid chromatography.

    PubMed

    Racha, El-Debs; Gay, Pauline; Dugas, Vincent; Demesmay, Claire

    2016-03-01

    A new vinyltrimethoxysilane-based hybrid silica monolith was developed and used as a reversed-phase capillary column. The synthesis of this rich vinyl hybrid macroporous monolith, by cocondensation of vinyltrimethoxysilane with tetramethoxysilane, was investigated using an unconventional (formamide, nitric acid) porogen/catalyst system. A macroporous hybrid silica monolith with 80% in mass of vinyltrimethoxysilane in the feeding silane solution was obtained and compared to a more conventional low vinyl content hybrid monolith with only of 20% vinyltrimethoxysilane. Monoliths were characterized by scanning electron microscopy, (29) Si nuclear magnetic resonance spectroscopy and N2 adsorption-desorption. About 80% of the vinyl precursor was incorporated in the final materials, leading to 15.9 and 61.5% of Si atoms bonded to vinyl groups for 20% vinyltrimethoxysilane and 80% vinyltrimethoxysilane, respectively. The 80% vinyltrimethoxysilane monolith presents a lower surface area than 20% vinyltrimethoxysilane (159 versus 551 m(2) /g), which is nevertheless compensated by a higher vinyl surface density. Chromatographic properties were evaluated in reversed-phase mode. Plots of ln(k) versus percentage of organic modifier were used to assess the reversed-phase mechanism. Its high content of organic groups leads to high retention properties. Column efficiencies of 170 000 plates/m were measured for this 80% vinyltrimethoxysilane hybrid silica monolith. Long capillary monolithic columns (90 cm) were successfully synthesized (N = 120 000).

  2. Vinyl chloride and polyvinyl chloride.

    PubMed

    Lewis, R

    1999-01-01

    Polyvinyl chloride (PVC) is an important plastic resin for construction, pipe and tubing, siding, and other uses. Exposures to vinyl chloride monomer during the early years of production resulted in an important sentinel health event: the recognition of an excess of a rare liver cancer, hepatic angiosarcoma, at facilities throughout the world. Several other syndromes, including acro-osteolysis, also have been associated with PVC, but less clearly with vinyl chloride. Extensive research ranging from large-scale epidemiologic studies to biomarker research into molecular mechanisms continues to provide valuable insight into the pathogenesis of occupational cancer.

  3. Clickable Periodic Mesoporous Organosilica Monolith for Highly Efficient Capillary Chromatographic Separation.

    PubMed

    Wu, Ci; Liang, Yu; Yang, Kaiguang; Min, Yi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-02-01

    A novel clickable periodic mesoporous organosilica monolith with the surface area up to 1707 m(2) g(-1) was in situ synthesized in the capillary by the one-step condensation of the organobridged-bonded alkoxysilane precursor bis(triethoxysilyl)ethylene. With Si-C bonds in the skeleton, the monolith possesses excellent chemical and mechanical stability. With vinyl groups highly loaded and homogeneously distributed throughout the structure, the monolith can be readily functionalized with functional groups by effective thiol-ene "click" chemistry reaction. Herein, with "click" modification of C18, the obtained monolith was successfully applied for capillary liquid chromatographic separation of small molecules and proteins. The column efficiency could reach 148,000 N/m, higher than most reported hybrid monoliths. Moreover, intact proteins could be separated well with good reproducibility, even after the monolithic column was exposed by basic mobile phase (pH 10.0) overnight, demonstrating the great promising of such monolith for capillary chromatographic separation. PMID:26751092

  4. Clickable Periodic Mesoporous Organosilica Monolith for Highly Efficient Capillary Chromatographic Separation.

    PubMed

    Wu, Ci; Liang, Yu; Yang, Kaiguang; Min, Yi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-02-01

    A novel clickable periodic mesoporous organosilica monolith with the surface area up to 1707 m(2) g(-1) was in situ synthesized in the capillary by the one-step condensation of the organobridged-bonded alkoxysilane precursor bis(triethoxysilyl)ethylene. With Si-C bonds in the skeleton, the monolith possesses excellent chemical and mechanical stability. With vinyl groups highly loaded and homogeneously distributed throughout the structure, the monolith can be readily functionalized with functional groups by effective thiol-ene "click" chemistry reaction. Herein, with "click" modification of C18, the obtained monolith was successfully applied for capillary liquid chromatographic separation of small molecules and proteins. The column efficiency could reach 148,000 N/m, higher than most reported hybrid monoliths. Moreover, intact proteins could be separated well with good reproducibility, even after the monolithic column was exposed by basic mobile phase (pH 10.0) overnight, demonstrating the great promising of such monolith for capillary chromatographic separation.

  5. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    PubMed

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture.

  6. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    PubMed

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture. PMID:27473483

  7. Monolithic tandem solar cell

    DOEpatents

    Wanlass, Mark W.

    1991-01-01

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

  8. Monolithic microfluidic concentrators and mixers

    DOEpatents

    Frechet, Jean M.; Svec, Frantisek; Yu, Cong; Rohr, Thomas

    2005-05-03

    Microfluidic devices comprising porous monolithic polymer for concentration, extraction or mixing of fluids. A method for in situ preparation of monolithic polymers by in situ initiated polymerization of polymer precursors within microchannels of a microfluidic device and their use for solid phase extraction (SPE), preconcentration, concentration and mixing.

  9. High surface area, high permeability carbon monoliths

    SciTech Connect

    Lagasse, R.R.; Schroeder, J.L.

    1994-12-31

    The goal of this work is to prepare carbon monoliths having precisely tailored pore size distribution. Prior studies have demonstrated that poly(acrylonitrile) can be processed into a precursor having tailored macropore structure. Since the macropores were preserved during pyrolysis, this synthetic process provided a route to porous carbon having macropores with size =0.1 to 10{mu}m. No micropores of size <2 nm could be detected in the carbon, however, by nitrogen adsorption. In the present work, the authors have processed a different polymer, poly(vinylidene chloride) into a macroporous precursor, Pyrolysis produced carbon monoliths having macropores derived from the polymer precursor as well as extensive microporosity produced during the pyrolysis of the polymer. One of these carbons had BET surface area of 1,050 m{sup 2}/g and about 1.2 cc/g total pore volume, with about 1/3 of the total pore volume in micropores and the remainder in 1{mu}m macropores. No mesopores in the intermediate size range could be detected by nitrogen adsorption. Carbon materials having high surface area as well as micron size pores have potential applications as electrodes for double layer supercapacitors containing liquid electrolyte, or as efficient media for performing chemical separations.

  10. Design of monoliths through their mechanical properties.

    PubMed

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  11. Polyoxometalate incorporated porous polymer monoliths, a versatile separation media for nano liquid chromatography.

    PubMed

    Zhang, Zheng; Xu, Jing; Hussain, Dilshad; Feng, Yu-Qi

    2016-07-01

    Here in, we present a strategy to incorporate NBu4SiW11O39(SiCHCH2)2, an organic-modified polyoxometalates (POM) monomer, into the monolithic poly(butyl methacrylate-co-ethylene glycol dimethacrylate) capillary columns. SEM analysis and permeability test indicated that the addition of POM lead to larger skeleton size and better permeability. BET and pore size distribution test confirmed the uniform porosity of the resulting POM incorporated monoliths. Hydrophobic, strong cation-exchange and H-bond interactions of the prepared monolith were evaluated by testing a series of chromatographic probes. The performance of monolith was further elaborated by separating 5 nucleobases, and 6 neurotransmitters. Chromatographic separation results showed that POM incorporated monolith exhibited much better resolution for the analytes as compared to the monolith without POM. This type of monolithic material has been reported for the first time and the work provided a promising way for preparation and application of various POM-incorporated monolithic materials in separation science. PMID:27236481

  12. Polyoxometalate incorporated porous polymer monoliths, a versatile separation media for nano liquid chromatography.

    PubMed

    Zhang, Zheng; Xu, Jing; Hussain, Dilshad; Feng, Yu-Qi

    2016-07-01

    Here in, we present a strategy to incorporate NBu4SiW11O39(SiCHCH2)2, an organic-modified polyoxometalates (POM) monomer, into the monolithic poly(butyl methacrylate-co-ethylene glycol dimethacrylate) capillary columns. SEM analysis and permeability test indicated that the addition of POM lead to larger skeleton size and better permeability. BET and pore size distribution test confirmed the uniform porosity of the resulting POM incorporated monoliths. Hydrophobic, strong cation-exchange and H-bond interactions of the prepared monolith were evaluated by testing a series of chromatographic probes. The performance of monolith was further elaborated by separating 5 nucleobases, and 6 neurotransmitters. Chromatographic separation results showed that POM incorporated monolith exhibited much better resolution for the analytes as compared to the monolith without POM. This type of monolithic material has been reported for the first time and the work provided a promising way for preparation and application of various POM-incorporated monolithic materials in separation science.

  13. Characterization of supermacroporous monolithic polyacrylamide based matrices designed for chromatography of bioparticles.

    PubMed

    Plieva, Fatima M; Savina, Irina N; Deraz, Sahar; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-25

    Supermacroporous monolithic acrylamide (AAm)-based cryogels were prepared by radical cryo-polymerizaton (polymerization in the moderately frozen system) of AAm with functional monomers and cross-linker N,N'-methylene-bis-acrylamide (MBAAm). Electron microscopy studies revealed supermacroporous structure of the developed cryogels with pore size of 5-100 microm. Cryogel porosity depended on cryo-polymerization conditions. More than 90% of the monolithic bed volume is the interconnected supermacropores filled with water and less than 10% of the monolithic volume is pore walls. The total protein binding capacity (lysozyme in the case of immobilized metal affinity chromatography (IMAC) column and bovine serum albumin (BSA) in the case of anion-exchange (AE) column) was independent of the flow rates till 600 cm/h. Chromatographic behavior of E. coli cells when a cell suspension was applied to ion-exchange cryogel columns depended on both the density of functional ligand and the porosity of the cryogel.

  14. Characterization of supermacroporous monolithic polyacrylamide based matrices designed for chromatography of bioparticles.

    PubMed

    Plieva, Fatima M; Savina, Irina N; Deraz, Sahar; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-25

    Supermacroporous monolithic acrylamide (AAm)-based cryogels were prepared by radical cryo-polymerizaton (polymerization in the moderately frozen system) of AAm with functional monomers and cross-linker N,N'-methylene-bis-acrylamide (MBAAm). Electron microscopy studies revealed supermacroporous structure of the developed cryogels with pore size of 5-100 microm. Cryogel porosity depended on cryo-polymerization conditions. More than 90% of the monolithic bed volume is the interconnected supermacropores filled with water and less than 10% of the monolithic volume is pore walls. The total protein binding capacity (lysozyme in the case of immobilized metal affinity chromatography (IMAC) column and bovine serum albumin (BSA) in the case of anion-exchange (AE) column) was independent of the flow rates till 600 cm/h. Chromatographic behavior of E. coli cells when a cell suspension was applied to ion-exchange cryogel columns depended on both the density of functional ligand and the porosity of the cryogel. PMID:15177170

  15. Monolithic THz Frequency Multipliers

    NASA Technical Reports Server (NTRS)

    Erickson, N. R.; Narayanan, G.; Grosslein, R. M.; Martin, S.; Mehdi, I.; Smith, P.; Coulomb, M.; DeMartinez, G.

    2001-01-01

    Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.

  16. Monolithic ballasted penetrator

    DOEpatents

    Hickerson, Jr., James P.; Zanner, Frank J.; Baldwin, Michael D.; Maguire, Michael C.

    2001-01-01

    The present invention is a monolithic ballasted penetrator capable of delivering a working payload to a hardened target, such as reinforced concrete. The invention includes a ballast made from a dense heavy material insert and a monolithic case extending along an axis and consisting of a high-strength steel alloy. The case includes a nose end containing a hollow portion in which the ballast is nearly completely surrounded so that no movement of the ballast relative to the case is possible during impact with a hard target. The case is cast around the ballast, joining the two parts together. The ballast may contain concentric grooves or protrusions that improve joint strength between the case and ballast. The case further includes a second hollow portion; between the ballast and base, which has a payload fastened within this portion. The penetrator can be used to carry instrumentation to measure the geologic character of the earth, or properties of arctic ice, as they pass through it.

  17. Mepiquat chloride

    Integrated Risk Information System (IRIS)

    Mepiquat chloride ; CASRN 24307 - 26 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

  18. Methyl chloride

    Integrated Risk Information System (IRIS)

    Methyl chloride ; CASRN 74 - 87 - 3 ( 07 / 17 / 2001 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  19. Ethyl chloride

    Integrated Risk Information System (IRIS)

    Ethyl chloride ; CASRN 75 - 00 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  20. Benzyl chloride

    Integrated Risk Information System (IRIS)

    Benzyl chloride ; CASRN 100 - 44 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  1. Vinyl chloride

    Integrated Risk Information System (IRIS)

    Vinyl chloride ; CASRN 75 - 01 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  2. Acetyl chloride

    Integrated Risk Information System (IRIS)

    Acetyl chloride ; CASRN 75 - 36 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  3. Hydrogen chloride

    Integrated Risk Information System (IRIS)

    Hydrogen chloride ; CASRN 7647 - 01 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  4. Allyl chloride

    Integrated Risk Information System (IRIS)

    Allyl chloride ; CASRN 107 - 05 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  5. Monolithic microchannel heatsink

    DOEpatents

    Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

    1996-01-01

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

  6. Monolithic microchannel heatsink

    DOEpatents

    Benett, W.J.; Beach, R.J.; Ciarlo, D.R.

    1996-08-20

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density. 9 figs.

  7. Monolithic freeform element

    NASA Astrophysics Data System (ADS)

    Kiontke, Sven R.

    2015-09-01

    For 10 years there has been the asphere as one of the new products to be accepted by the market. All parts of the chain design, production and measurement needed to learn how to treat the asphere and what it is helpful for. The aspheric optical element now is established and accepted as an equal optical element between other as a fast growing part of all the optical elements. Now we are focusing onto the next new element with a lot of potential, the optical freeform surface. Manufacturing results will be shown for fully tolerance optic including manufacturing, setup and optics configurations including measurement setup. The element itself is a monolith consisting of several optical surfaces that have to be aligned properly to each other. The freeform surface is measured for surface form tolerance (irregularity, slope, Zernike, PV).

  8. Monolithically compatible impedance measurement

    DOEpatents

    Ericson, Milton Nance; Holcomb, David Eugene

    2002-01-01

    A monolithic sensor includes a reference channel and at least one sensing channel. Each sensing channel has an oscillator and a counter driven by the oscillator. The reference channel and the at least one sensing channel being formed integrally with a substrate and intimately nested with one another on the substrate. Thus, the oscillator and the counter have matched component values and temperature coefficients. A frequency determining component of the sensing oscillator is formed integrally with the substrate and has an impedance parameter which varies with an environmental parameter to be measured by the sensor. A gating control is responsive to an output signal generated by the reference channel, for terminating counting in the at least one sensing channel at an output count, whereby the output count is indicative of the environmental parameter, and successive ones of the output counts are indicative of changes in the environmental parameter.

  9. Optimization of human serum albumin monoliths for chiral separations and high-performance affinity chromatography

    PubMed Central

    Pfaunmiller, Erika L.; Hartmann, Mahli; Dupper, Courtney M.; Soman, Sony; Hage, David S.

    2012-01-01

    Various organic-based monoliths were prepared and optimized for immobilization of the protein human serum albumin (HSA) as a binding agent for chiral separations and high-performance affinity chromatography. These monoliths contained co-polymers based on glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EDMA) or GMA and trimethylolpropane trimethacrylate (TRIM). A mixture of cyclohexanol and 1-dodecanol was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. These monoliths were used with both the Schiff base and epoxy immobilization methods and measured for their final content of HSA. Monoliths showing the highest protein content were further evaluated in chromatographic studies using R/S-warfarin and d/l-tryptophan as model chiral solutes. A 2.6–2.7-fold increase in HSA content was obtained in the final monoliths when compared to similar HSA monoliths prepared according to the literature. The increased protein content made it possible for the new monoliths to provide higher retention and/or two-fold faster separations for the tested solutes when using 4.6 mm i.d. × 50 mm columns. These monoliths were also used to create 4.6 mm i.d. × 10 mm HSA microcolumns that could separate the same chiral solutes in only 1.5–6.0 min. The approaches used in this study could be extended to the separation of other chiral solutes and to the optimization of organic monoliths for use with additional proteins as binding agents. PMID:23010249

  10. Organic monolith frits encased in polyether ether ketone tubing with improved durability for liquid chromatography.

    PubMed

    Park, Sin Young; Cheong, Won Jo

    2015-09-01

    This study introduces a preparation method for polymer-encased monolith frits with improved durability for liquid chromatography columns. The inner surface of the polyether ether ketone tubing is pretreated with sulfuric acid in the presence of catalysts (vanadium oxide and sodium sulfate). The tubing was rinsed with water and acetone, flushed with nitrogen, and treated with glycidyl methacrylate. After washing, the monolith reaction mixture composed of lauryl methacrylate, ethylene glycol dimethacrylate, initiator, and porogenic solvent was filled in the tubing and subjected to in situ polymerization. The tubing was cut into thin slices and used as frits for microcolumns. To check their durability, the frit slices were placed in a vial and a heavy impact was applied on the vial by a vortex mixer for various periods. The frits made in the presence of catalysts were found to be more durable than those made without catalysts. Furthermore, when the monolith-incorporated tubing was used as a chromatography column, the column prepared in the presence of catalysts resulted in a better separation efficiency. The separation performance of the columns installed with the polyether ether ketone encased monolith frits was comparable to that of the columns installed with the commercial stainless-steel screen frits.

  11. Performance of single particle fritted capillary columns in electrochromatography.

    PubMed

    Zhang, Bo; Liu, Qing; Yang, Lijun; Wang, Qiuquan

    2013-01-11

    Development of capillary electrochromatography (CEC) largely depends on column technology. The past ten years or so have seen a great number of CEC works performed on monolithic columns, due to simplicity and robustness in column fabrication. Monolithic columns eliminate the issue of column fritting, which conventionally made particle-packed capillary columns fragile and introduced nonuniformity to the chromatographic bed. The particulate packing material, however, is still a popular type of stationary phase widely used in CEC, as the rich library of HPLC packing material provides a wide range of choices for chromatographic separations performed in electrodriven mode. In this study, we investigated a purely physical fritting method, single particle fritting technology, to immobilize particulate chromatographic material inside capillary tube in a sinter-free manner to produce robust capillary columns. Single particle fritted columns present significantly improved column-to-column reproducibility (n=10) in peak efficiency, retention factor, peak area and asymmetry (%RSD=5.4, 7.7, 6.2 and 6.1, respectively, at 26 kV), enabling their practical application in high throughput parallel analysis using multiple columns.

  12. Monolithic microcircuit techniques and processes

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1972-01-01

    Brief discussions of the techniques used to make dielectric and metal thin film depositions for monolithic circuits are presented. Silicon nitride deposition and the properties of silicon nitride films are discussed. Deposition of dichlorosilane and thermally grown silicon dioxide are reported. The deposition and thermal densification of borosilicate, aluminosilicate, and phosphosilicate glasses are discussed. Metallization for monolithic circuits and the characteristics of thin films are also included.

  13. Ground, sieved, and C18 modified monolithic silica particles for packing material of microcolumn high-performance liquid chromatography.

    PubMed

    Ko, Joung Ho; Baik, Yoon Suk; Park, Seong Tae; Cheong, Won Jo

    2007-03-16

    We here report a new type of stationary phase for microcolumns. C18 modified silica monolith particles were prepared by grinding and sieving the silica monolith followed by C18 modification and end-capping, and were used as packing material. Ground silica monolith particles were not spherical but irregular with some residual monolithic network structure. The separation efficiency of the stationary phase made of sieved monolith particles (5-10 microm) was better than that of the stationary phase made of unsieved particles. The microcolumn packed with the sieved C18 ground monolith particles (5-10 microm) showed quite good separation efficiency (height equivalent to theoretical plate, HETP, as low as 15 microm) and it was even superior to the microcolumn packed with a commercial spherical 5 microm C18 stationary phase. The column pressure drop of C18 monolith particles was about two-third of that of the commercial spherical C18 phase. The preparation method of C18 stationary phase with ground and sieved silica monolith particles presumably suggests advantages of simplicity and convenience in modification and washing procedures compared to bulk silica monolith. It also showed both improved separation efficiency and low back pressure. PMID:17289065

  14. Preparation of phenylboronate affinity rigid monolith with macromolecular porogen.

    PubMed

    Li, Xiang-Jie; Jia, Man; Zhao, Yong-Xin; Liu, Zhao-Sheng; Akber Aisa, Haji

    2016-03-18

    Boronate-affinity monolithic column was first prepared via polystyrene (PS) as porogen in this work. The monolithic polymer was synthetized using 4-vinylphenylboronic acid (4-VPBA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as crosslinker monomer, and a mixture of PS solution in tetrahydrofuran, the linear macromolecular porogen, and toluene as porogen. Isoquercitrin (ISO) and hyperoside (HYP), isomer diol flavonoid glycosides, can be baseline separated on the poly(VPBA-co-EDMA) monolith. The effect of polymerization variables on the selectivity factor, e.g., the ratio of monomer to crosslinker (M/C), the amount of PS and the molecular weight of macromolecular porogen was investigated. The surface properties of the monolithic polymer were characterized by scanning electron microscopy and nitrogen adsorption. The best polymerization condition was the M/C ratio of 7:3, and the PS concentration of 40 mg/ml. The poly(VPBA-co-EDMA) polymer was also applied to extract cis-diol flavonoid glycosides from the crude extraction of cotton flower. After treated by poly(VPBA-co-EDMA) for solid phase extraction, high purity ISO and HYP (>99.96%) can be obtained with recovery of 83.7% and 78.6%, respectively. PMID:26896914

  15. Preparation of phenylboronate affinity rigid monolith with macromolecular porogen.

    PubMed

    Li, Xiang-Jie; Jia, Man; Zhao, Yong-Xin; Liu, Zhao-Sheng; Akber Aisa, Haji

    2016-03-18

    Boronate-affinity monolithic column was first prepared via polystyrene (PS) as porogen in this work. The monolithic polymer was synthetized using 4-vinylphenylboronic acid (4-VPBA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as crosslinker monomer, and a mixture of PS solution in tetrahydrofuran, the linear macromolecular porogen, and toluene as porogen. Isoquercitrin (ISO) and hyperoside (HYP), isomer diol flavonoid glycosides, can be baseline separated on the poly(VPBA-co-EDMA) monolith. The effect of polymerization variables on the selectivity factor, e.g., the ratio of monomer to crosslinker (M/C), the amount of PS and the molecular weight of macromolecular porogen was investigated. The surface properties of the monolithic polymer were characterized by scanning electron microscopy and nitrogen adsorption. The best polymerization condition was the M/C ratio of 7:3, and the PS concentration of 40 mg/ml. The poly(VPBA-co-EDMA) polymer was also applied to extract cis-diol flavonoid glycosides from the crude extraction of cotton flower. After treated by poly(VPBA-co-EDMA) for solid phase extraction, high purity ISO and HYP (>99.96%) can be obtained with recovery of 83.7% and 78.6%, respectively.

  16. A monolithically-integrated μGC chemical sensor system.

    PubMed

    Manginell, Ronald P; Bauer, Joseph M; Moorman, Matthew W; Sanchez, Lawrence J; Anderson, John M; Whiting, Joshua J; Porter, Daniel A; Copic, Davor; Achyuthan, Komandoor E

    2011-01-01

    Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response, micro-gas chromatography (μGC) system is essential for such applications. We describe the design, fabrication and packaging of μGC on monolithically-integrated Si dies, comprised of a preconcentrator (PC), μGC column, detector and coatings for each of these components. An important feature of our system is that the same mechanical micro resonator design is used for the PC and detector. We demonstrate system performance by detecting four different CWA simulants within 2 min. We present theoretical analyses for cost/power comparisons of monolithic versus hybrid μGC systems. We discuss thermal isolation in monolithic systems to improve overall performance. Our monolithically-integrated μGC, relative to its hybrid cousin, will afford equal or slightly lower cost, a footprint that is 1/2 to 1/3 the size and an improved resolution of 4 to 25%. PMID:22163970

  17. Weak anion exchange chromatographic profiling of glycoprotein isoforms on a polymer monolithic capillary.

    PubMed

    Liu, Jing; Ren, Lianbing; Liu, Yunchun; Li, Hengye; Liu, Zhen

    2012-03-01

    High resolution separation of intact glycoproteins, which is essential for many aspects such as finger-print profiling, represents a great challenge because one glycoprotein can exhibit many isoforms with close physicochemical properties. Monolithic columns are important separation media for the separation of intact proteins due to its significant advantages such as easy preparation, high column efficiency and high permeability. However, there are few reports on high resolution profiling of intact glycoproteins. Herein, we presented a polymeric weak anion exchange (WAX) monolithic capillary for high resolution separation of glycoprotein isoforms. A base monolith was first prepared through ring-opening polymerization between tris(2,3-epoxypropyl)isocyanurate and tri(2-aminoethyl), and then modified through reacting with ammonia aqueous solution to convert the unreacted epoxide moieties into primary amino groups. The prepared monolithic capillary was characterized in terms of morphology, pore size, hydrophilicity and reproducibility. The obtained WAX monolithic capillary exhibited desired through-pores and mesopore size, stable skeleton and hydrophilic nature. The performance of the capillary was evaluated using several typical glycoproteins such as α(1)-acid glycoprotein (AGP) as mode analytes. Effects of the experimental parameters on the glycoform resolution were investigated. Under the optimized separation conditions, the tested glycoproteins were all resolved into distinct glycoforms. A comparative investigation with capillary zone electrophoresis (CZE) revealed that this WAX column provided better selectivity as more isoforms were observed, although the resolution of some glycoprotein isoforms decreased.

  18. One-pot preparation of a novel monolith for high performance liquid chromatography applications.

    PubMed

    Jiao, Xiaoyan; Shen, Shigang; Shi, Tiesheng

    2015-12-15

    Various novel porous organic-based monoliths with the mode of hydrophobicity were synthesized by in situ free-radical crosslinking copolymerization and optimized for the separations of small molecules and high-performance reversed-phase chromatography (RP-chromatography). These monoliths contained co-polymers based on glycidyl methacrylate (GMA)/ethylene glycol dimethacrylate (EDMA)/tripropylene glycol diacrylate (TPGDA) or EDMA/TPGDA. A mixture of cetanol, methanol and poly (ethylene glycol) (PEG) was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. The conditions were optimized and the resulting poly (GMA-co-TPGDA-co-EDMA) monolith was investigated by infrared spectrometer (IR), field emission scanning electron microscope (FESEM), and mercury intrusion porosimetry (MIP), respectively. The column performance was assessed by the separation of a series of neutral solutes of benzene derivatives. The result demonstrated that the prepared monolith exhibited an RP-chromatographic behavior and relatively homogeneous structure, good permeability and separation performance. Moreover, the relative standard deviations (RSDs) of the retention factor values for benzene derivatives were less than 1.5% (n=7, column-to-column). The approach used in this study was extended to the separation of anilines.

  19. PULSE COLUMN

    DOEpatents

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  20. Self-interaction chromatography of proteins on a microfluidic monolith

    PubMed Central

    Martin, Cristina; Lenhoff, Abraham M.

    2010-01-01

    A novel miniaturized system has been developed for measuring protein-protein interactions in solution with high efficiency and speed, and minimal use of protein. A chromatographic monolith synthesized in a capillary is used in the method to make interaction measurements by self-interaction chromatography (SIC) in a manner that, compared to column methods, is more efficient as well as more readily practicable even if only small amounts of protein are available. The microfluidic monolith requires much less protein for both column synthesis and the chromatographic measurements than a conventional SIC system, and in addition offers improved mass transfer and hence higher chromatographic efficiency than for previous SIC miniaturization systems. Protein self-interactions for catalase as a model protein, quantified by measurement of second virial coefficients, B22, were determined by SIC and follow trends that are consistent with previously reported values. Different column derivatization conditions were studied in order to optimize the chromatographic behavior of the microfluidic system for SIC measurements. Chromatographic sensitivity can be further increased by using different column synthesis conditions. PMID:21258647

  1. A novel positively charged achiral co-monomer for β-cyclodextrin monolithic stationary phase: improved chiral separation of acidic compounds using capillary electrochromatography coupled to mass spectrometry.

    PubMed

    Bragg, William; Shamsi, Shahab A

    2012-12-01

    The work presented here demonstrates the incorporation of vinylbenzyl trimethylammonium (VBTA) as a novel positively charged achiral co-monomer to a glycidyl methacrylate-beta cyclodextrin (GMA/β-CD) based monolith, providing anion exchange sites with reversed electroosmotic flow (EOF) for capillary electrochromatography (CEC). The monolithic phases, GMA/β-CD-VBTA and GMA/β-CD (without co-monomer) were characterized by scanning electron microscopy, optical microscopy, pressure drop/flow-rate curves and nitrogen adsorption analysis. After optimizing the stationary phase and mobile phase parameters, chiral separations of 41 pairs of structurally diverse anionic chiral analytes were compared individually using the GMA/β-CD-VBTA and GMA/β-CD monolithic columns. The GMA/β-CD-VBTA monolith chiral stationary phase separated significantly more acidic compounds compared to the GMA/β-CD column. To-date there has been limited work in the development of chiral monolithic column for CEC-mass spectrometry (MS). Because of good electrodriven flow characteristics, which allow the column to maintain a stable current in the absence of outlet vial, GMA/β-CD-VBTA column was successfully coupled to single quadrupole mass spectrometer for CEC-MS of several chiral test compounds. In addition, the same monolithic CEC column when coupled to a triple quadrupole MS instrument, two orders of magnitude higher sensitivity was observed compared to a single quadrupole MS instrument.

  2. Monolithic metal oxide transistors.

    PubMed

    Choi, Yongsuk; Park, Won-Yeong; Kang, Moon Sung; Yi, Gi-Ra; Lee, Jun-Young; Kim, Yong-Hoon; Cho, Jeong Ho

    2015-04-28

    We devised a simple transparent metal oxide thin film transistor architecture composed of only two component materials, an amorphous metal oxide and ion gel gate dielectric, which could be entirely assembled using room-temperature processes on a plastic substrate. The geometry cleverly takes advantage of the unique characteristics of the two components. An oxide layer is metallized upon exposure to plasma, leading to the formation of a monolithic source-channel-drain oxide layer, and the ion gel gate dielectric is used to gate the transistor channel effectively at low voltages through a coplanar gate. We confirmed that the method is generally applicable to a variety of sol-gel-processed amorphous metal oxides, including indium oxide, indium zinc oxide, and indium gallium zinc oxide. An inverter NOT logic device was assembled using the resulting devices as a proof of concept demonstration of the applicability of the devices to logic circuits. The favorable characteristics of these devices, including (i) the simplicity of the device structure with only two components, (ii) the benign fabrication processes at room temperature, (iii) the low-voltage operation under 2 V, and (iv) the excellent and stable electrical performances, together support the application of these devices to low-cost portable gadgets, i.e., cheap electronics. PMID:25777338

  3. Monolithic afocal telescope

    NASA Technical Reports Server (NTRS)

    Roberts, William T. (Inventor)

    2010-01-01

    An afocal monolithic optical element formed of a shallow cylinder of optical material (glass, polymer, etc.) with fast aspheric surfaces, nominally confocal paraboloids, configured on the front and back surfaces. The front surface is substantially planar, and this lends itself to deposition of multi-layer stacks of thin dielectric and metal films to create a filter for rejecting out-of-band light. However, an aspheric section (for example, a paraboloid) can either be ground into a small area of this surface (for a Cassegrain-type telescope) or attached to the planar surface (for a Gregorian-type telescope). This aspheric section of the surface is then silvered to create the telescope's secondary mirror. The rear surface of the cylinder is figured into a steep, convex asphere (again, a paraboloid in the examples), and also made reflective to form the telescope's primary mirror. A small section of the rear surface (approximately the size of the secondary obscuration, depending on the required field of the telescope) is ground flat to provide an unpowered surface through which the collimated light beam can exit the optical element. This portion of the rear surface is made to transmit the light concentrated by the reflective surfaces, and can support the deposition of a spectral filter.

  4. Factorizing monolithic applications

    SciTech Connect

    Hall, J.H.; Ankeny, L.A.; Clancy, S.P.

    1998-12-31

    The Blanca project is part of the US Department of Energy`s (DOE) Accelerated Strategic Computing Initiative (ASCI), which focuses on Science-Based Stockpile Stewardship through the large-scale simulation of multi-physics, multi-dimensional problems. Blanca is the only Los Alamos National Laboratory (LANL)-based ASCI project that is written entirely in C++. Tecolote, a new framework used in developing Blanca physics codes, provides an infrastructure for gluing together any number of components; this framework is then used to create applications that encompass a wide variety of physics models, numerical solution options, and underlying data storage schemes. The advantage of this approach is that only the essential components for the given model need be activated at runtime. Tecolote has been designed for code re-use and to isolate the computer science mechanics from the physics aspects as much as possible -- allowing physics model developers to write algorithms in a style quite similar to the underlying physics equations that govern the computational physics. This paper describes the advantages of component architectures and contrasts the Tecolote framework with Microsoft`s OLE and Apple`s OpenDoc. An actual factorization of a traditional monolithic application into its basic components is also described.

  5. Assessment of the Grouted IXC Monolith in Support of K East Basin Hazard Categorization

    SciTech Connect

    Short, Steven M.; Dodson, Michael G.; Alzheimer, James M.; Meyer, Perry A.

    2007-10-12

    Addendum to original report updating the structural analysis of the I-beam accident to reflect a smaller I-beam than originally assumed (addendum is 2 pages). The K East Basin currently contains six ion exchange columns (IXCs) that were removed from service over 10 years ago. Fluor Hanford plans to immobilize the six ion exchange columns (IXCs) in place in a concrete monolith. PNNL performed a structural assessment of the concrete monolith to determine its capability to absorb the forces imposed by postulated accidents and protect the IXCs from damage and thus prevent a release of radioactive material. From this assessment, design specifications for the concrete monolith were identified that would prevent a release of radioactive material for any of the postulated hazardous conditions.

  6. Covalent attachment of polymeric monolith to polyether ether ketone (PEEK) tubing.

    PubMed

    Lv, Chunguang; Heiter, Jaana; Haljasorg, Tõiv; Leito, Ivo

    2016-08-17

    A new method of reproducible preparation of vinylic polymeric monolithic columns with a key step of covalently anchoring the monolith to PEEK surface is described. In order to chemically attach the polymer monolith to the tube wall, methacrylate functional groups were introduced onto PEEK surface by a three-step procedure, including surface etching, surface reduction and surface methacryloylation. The chemical state of the modified tubing surface was characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy. It was found that the etching step is the key to successfully modifying the PEEK tubing surface. Poly(styrene-co-divinylbenzene) monoliths were in situ synthesized by thermally initiated free radical copolymerization within the confines of surface-vinylized PEEK tubings of dimensions close to ones conventionally used in HPLC and UHPLC (1.6 mm internal diameter, 10.0-12.5 cm length). Adhesion test was done by measuring the operating pressure drop, which the prepared stationary phases can withstand. Good pressure resistance, up to 140 bar/10 cm (flow rate 0.5 mL min(-1), acetonitrile as a mobile phase), indicates strong bonding of monolith to the tubing wall. The monolithic material was proven to have a permeability of 1.7 × 10 (-14) m(2), applying acetonitrile-water 70:30 (v/v) as a mobile phase. The column performance was reproducible from column to column and was evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode (acetonitrile-water 70:30, v/v). The numbers of plates per meter at optimal flow rate were found to be between 26 000 and 32 000 for the different analytes.

  7. Covalent attachment of polymeric monolith to polyether ether ketone (PEEK) tubing.

    PubMed

    Lv, Chunguang; Heiter, Jaana; Haljasorg, Tõiv; Leito, Ivo

    2016-08-17

    A new method of reproducible preparation of vinylic polymeric monolithic columns with a key step of covalently anchoring the monolith to PEEK surface is described. In order to chemically attach the polymer monolith to the tube wall, methacrylate functional groups were introduced onto PEEK surface by a three-step procedure, including surface etching, surface reduction and surface methacryloylation. The chemical state of the modified tubing surface was characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy. It was found that the etching step is the key to successfully modifying the PEEK tubing surface. Poly(styrene-co-divinylbenzene) monoliths were in situ synthesized by thermally initiated free radical copolymerization within the confines of surface-vinylized PEEK tubings of dimensions close to ones conventionally used in HPLC and UHPLC (1.6 mm internal diameter, 10.0-12.5 cm length). Adhesion test was done by measuring the operating pressure drop, which the prepared stationary phases can withstand. Good pressure resistance, up to 140 bar/10 cm (flow rate 0.5 mL min(-1), acetonitrile as a mobile phase), indicates strong bonding of monolith to the tubing wall. The monolithic material was proven to have a permeability of 1.7 × 10 (-14) m(2), applying acetonitrile-water 70:30 (v/v) as a mobile phase. The column performance was reproducible from column to column and was evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode (acetonitrile-water 70:30, v/v). The numbers of plates per meter at optimal flow rate were found to be between 26 000 and 32 000 for the different analytes. PMID:27286776

  8. Radial heterogeneity of some analytical columns used in high-performance liquid chromatography

    SciTech Connect

    Mriziq, Khaled S; Guiochon, Georges A

    2009-01-01

    An on-column electrochemical microdetector was used to determine accurately the radial distribution of the mobile phase velocity and of the column efficiency at the exit of three common analytical columns, namely a 100 mm x 4.6 mm C18 bonded silica-based monolithic column, a 150 mm x 4.6 mm column packed with 2.7 {micro}m porous shell particles of C18 bonded silica (HALO), and a 150 mm x 4.6 mm column packed with 3 {micro}m fully porous C18 bonded silica particles (LUNA). The results obtained demonstrate that all three columns are not radially homogeneous. In all three cases, the efficiency was found to be lower in the wall region of the column than in its core region (the central core with a radius of 1/3 the column inner radius). The decrease in local efficiency from the core to the wall regions was lower in the case of the monolith (ca. 25%) than in that of the two particle-packed columns (ca. 35-50%). The mobile phase velocity was found to be ca. 1.5% higher in the wall than in the core region of the monolithic column while, in contrast, it was ca. 2.5-4.0% lower in the wall region for the two particle-packed columns.

  9. Enhancing the separation performance of the first-generation silica monolith using active flow technology: parallel segmented flow mode of operation.

    PubMed

    Soliven, Arianne; Foley, Dominic; Pereira, Luisa; Dennis, Gary R; Shalliker, R Andrew; Cabrera, Karin; Ritchie, Harald; Edge, Tony

    2014-03-21

    Active flow technology (AFT) columns are designed to minimise inefficient flow processes associated with the column wall and radial heterogeneity of the stationary phase bed. This study is the first to investigate AFT on an analytical scale 4.6mm internal diameter first-generation silica monolith. The performance was compared to a conventional first-generation silica monolith and it was observed that the AFT monolith had an increase in efficiency values that ranged from 15 to 111%; the trend demonstrating efficiency gains increasing as the volumetric flow to the detector was decreased, but with no loss in sensitivity.

  10. A new anion-exchange/hydrophobic monolith as stationary phase for nano liquid chromatography of small organic molecules and inorganic anions.

    PubMed

    Aydoğan, Cemil

    2015-05-01

    In this study, an anion-exchange/hydrophobic polymethacrylate-based stationary phase was prepared for nano-liquid chromatography of small organic molecules and inorganic anions. The stationary phase was synthesized by in situ polymerization of 3-chloro-2-hydroxypropylmethacrylate and ethylene dimethacrylate inside silanized 100 μm i.d. fused silica capillary. The porogen mixture consisted of toluene and dodecanol. The pore size distrubution profiles of the resulting monolith were determined by mercury intrusion porosimetry and the morphology of the prepared monolith was investigated by scanning electron microscope. Good permeability, stability and column efficiency were observed on the monolithic column with nano flow. The produced monolithic column, which contains reactive chloro groups, was then modified by reaction with N,N-dimethyl-N-dodecylamine to obtain an anion-exchange/hydrophobic monolithic stationary phase. The functionalized monolith contained ionizable amine groups and hydrophobic groups that are useful of anion-exchange/hydrophobic mixed-mode chromatography. The final monolithic column performance with respect to anion-exchange and hydrophobic interactions was assesed by the separation of alkylbenzene derivatives, phenolic compounds and inorganic anions, respectively. Theoretical plate numbers up to 23,000 plates/m were successfully achieved in the separation of inorganic anions.

  11. Column internals

    SciTech Connect

    Bravo, J.L.

    1998-02-01

    In the fields of distillation, absorption, stripping and extraction, theory and technology go hand in hand. The thermodynamic principles of phase equilibrium and the concepts of mass transfer and fluid flow are of primary importance in all of these operations. The engineer must understand these phenomena to select equipment effectively. This article discusses the latest in commercial technology in column internals for gas-liquid and liquid-liquid contacting. The principles of operation are explained vis-a-vis the characteristics of the applications in which they are used. The focus is on moderate-to-large columns for refining and chemical applications. Guidelines for selecting the most appropriate type of device are presented, and examples of typical applications are described.

  12. Separation of kafirins on surface porous RP-HPLC columns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface porous HPLC columns were investigated for the separation of kafarins, storage proteins of grain sorghum. Kafirins were successfully separated using C3, C8 and C18 surface porous stationary phases in less than 17 min. Separations using a monolithic C18 stationary phase were also developed ...

  13. Influence of the linking spacer length and type on the enantioseparation ability of β-cyclodextrin functionalized monoliths.

    PubMed

    Guo, Jialiang; Xiao, Yuan; Lin, Yuanjing; Zhang, Qiaoxuan; Chang, Yiqun; Crommen, Jacques; Jiang, Zhengjin

    2016-05-15

    In order to investigate the effect of the linking spacer on the enantioseparation ability of β-cyclodextrin (β-CD) functionalized polymeric monoliths, three β-CD-functionalized organic polymeric monoliths with different spacer lengths were prepared by using three amino-β-CDs, i.e. mono-6-amino-6-deoxy-β-CD, mono-6-ethylenediamine-6-deoxy-β-CD, mono-6-hexamethylenediamine-6-deoxy-β-CD, as starting materials. These amino-β-CDs reacted with glycidyl methacrylate to produce functional monomers which were then copolymerized with ethylene dimethacrylate. The enantioseparation ability of the three monoliths was evaluated using 14 chiral acidic compounds, including mandelic acid derivatives, nonsteroidal anti-inflammatory drugs, N-derivatized amino acids, and chiral herbicides under optimum chromatographic conditions. Notably, the poly(GMA-NH2-β-CD-co-EDMA) column provides higher enantioresolution and enantioselectivity than the poly(GMA-EDA-β-CD-co-EDMA) and poly(GMA-HDA-β-CD-co-EDMA) columns for most tested chiral analytes. Furthermore, the enantioseparation performance of triazole-linker containing monoliths was compared to that of ethylenediamine-linker containing monoliths. The results indicate that the enantioselectivity of β-CD monolithic columns is strongly related to the length and type of spacer tethering β-CD to the polymeric support. PMID:26992519

  14. Removing Chlorides From Metallurgical-Grade Silicon

    NASA Technical Reports Server (NTRS)

    Breneman, W. C.; Coleman, L. M.

    1982-01-01

    Process for making low-cost silicon for solar cells is further improved. Silane product recycled to feed stripper column converts some of heavy impurities to volatile ones that pass off at top of column with light wastes. Impurities--chlorides of arsenic, phosphorus, and boron-would otherwise be carried to subsequent distillations where they would be difficult to remove. Since only a small amount of silane is recycled, silicon production efficiency remains high.

  15. Monolithical aspherical beam expanding systems

    NASA Astrophysics Data System (ADS)

    Fuchs, U.; Matthias, Sabrina

    2014-10-01

    Beam expanding is a common task, where Galileo telescopes are preferred. However researches and customers have found limitations when using these systems. A new monolithical solution which is based on the usage of only one aspherical component will be presented. It will be shown how to combine up to five monolithical beam expanding systems and to keep the beam quality at diffraction limitation. Insights will be given how aspherical beam expanding systems will help using larger incoming beams and reducing the overall length of such a system. Additionally an add-on element for divergence and wavelength adaption will be presented.

  16. Method of monolithic module assembly

    DOEpatents

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-01-01

    Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  17. Monolithic precolumns as efficient tools for guiding the design of nanoparticulate drug-delivery formulations.

    PubMed

    Gatschelhofer, Christina; Prasch, Agnes; Buchmeiser, Michael R; Zimmer, Andreas; Wernig, Karin; Griesbacher, Martin; Pieber, Thomas R; Sinner, Frank M

    2012-09-01

    The development of nanomedicines for improved diagnosis and treatment of diseases is pushing current analytical methods to their limits. More efficient, quantitative high-throughput screening methods are needed to guide the optimization of promising nanoparticulate drug delivery formulations. In response to this need, we present herein a novel approach using monolithic separation media. The unique porosity of our capillary monolithic precolumns allows the direct injection and online removal of protamine-oligonucleotide nanoparticles ("proticles") without column clogging, thus avoiding the need for time-consuming off-line sample workup. Furthermore, ring-opening metathesis polymerization (ROMP)-derived monoliths show equivalent preconcentration efficiency for the target drug vasoactive intestinal peptide (VIP) as conventional particle-packed precolumns. The performance of the ROMP-derived monolithic precolumns was constant over at least 100 injections of crude proticle-containing and 300 injections of highly acidic samples. Applying a validated LC-MS/MS capillary monolithic column switching method, we demonstrate the rapid determination of both drug load and in vitro drug release kinetics of proticles within the critical first 2 h and investigate the stability of VIP-loaded proticles in aqueous storage medium intended for inhalation therapy.

  18. Affinity monolith chromatography: A review of principles and recent analytical applications

    PubMed Central

    Pfaunmiller, Erika L.; Paulemond, Marie Laura; Dupper, Courtney M.; Hage, David S.

    2012-01-01

    Affinity monolith chromatography (AMC) is a type of liquid chromatography that uses a monolithic support and a biologically-related binding agent as a stationary phase. AMC is a powerful method for the selective separation, analysis or studies of specific target compounds in a sample. This review discusses the basic principles of AMC and recent developments or applications of this method, with particular emphasis being given to work that has appeared in the last five years. Various materials that have been used to prepare columns for AMC are examined, including organic monoliths, silica monoliths, agarose monoliths and cryogels. These supports have been used in AMC for formats that have ranged from traditional columns to disks, microcolumns and capillaries. Many binding agents have also been employed in AMC, such as antibodies, enzymes, proteins, lectins, immobilized metal-ions and dyes. Some applications that have been reported with these binding agents in AMC are bioaffinity chromatography, immunoaffinity chromatography or immunoextraction, immobilized metal-ion affinity chromatography, dye-ligand affinity chromatography, chiral separations and biointeraction studies. Examples are presented from fields that include analytical chemistry, pharmaceutical analysis, clinical testing and biotechnology. Current trends and possible future directions in AMC are also discussed. PMID:23187827

  19. Chiral separation of acidic compounds using an O-9-(tert-butylcarbamoyl)quinidine functionalized monolith in micro-liquid chromatography.

    PubMed

    Wang, Qiqin; Zhu, Peijie; Ruan, Meng; Wu, Huihui; Peng, Kun; Han, Hai; Somsen, Govert W; Crommen, Jacques; Jiang, Zhengjin

    2016-04-29

    An O-9-(tert-butylcarbamoyl) quinidine (t-BuCQD) functionalized polymeric monolithic capillary column was prepared by the in situ copolymerization method. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy and micro-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained for this monolithic column. The chiral recognition ability of the resulting monolith was also evaluated using 47 N-derivatized amino acids, eight N-derivatized dipeptides, and two herbicides. Under the selected conditions, the enantiomers of all chiral analytes were baseline separated with exceptionally high selectivity and resolution using micro-LC. It is worth noting that this chiral stationary phase (CSP) containing quinidine with a tert-butyl carbamate residue as chiral selector exhibits much higher enantioselectivity and diastereoselectivity than the previously developed O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine (MQD) based CSP for N-derivatized amino acids and dipeptides. These results indicate that this novel quinidine-based polymeric monolith can be used as an effective tool for the enantioseparation of chiral acidic compounds.

  20. Chiral separation of acidic compounds using an O-9-(tert-butylcarbamoyl)quinidine functionalized monolith in micro-liquid chromatography.

    PubMed

    Wang, Qiqin; Zhu, Peijie; Ruan, Meng; Wu, Huihui; Peng, Kun; Han, Hai; Somsen, Govert W; Crommen, Jacques; Jiang, Zhengjin

    2016-04-29

    An O-9-(tert-butylcarbamoyl) quinidine (t-BuCQD) functionalized polymeric monolithic capillary column was prepared by the in situ copolymerization method. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy and micro-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained for this monolithic column. The chiral recognition ability of the resulting monolith was also evaluated using 47 N-derivatized amino acids, eight N-derivatized dipeptides, and two herbicides. Under the selected conditions, the enantiomers of all chiral analytes were baseline separated with exceptionally high selectivity and resolution using micro-LC. It is worth noting that this chiral stationary phase (CSP) containing quinidine with a tert-butyl carbamate residue as chiral selector exhibits much higher enantioselectivity and diastereoselectivity than the previously developed O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine (MQD) based CSP for N-derivatized amino acids and dipeptides. These results indicate that this novel quinidine-based polymeric monolith can be used as an effective tool for the enantioseparation of chiral acidic compounds. PMID:27038701

  1. Chemical anchoring of lauryl methacrylate-based reversed phase monolith to 1/16″ o.d. polyetheretherketone tubing.

    PubMed

    Shu, Shin; Kobayashi, Hiroharu; Okubo, Masaki; Sabarudin, Akhmad; Butsugan, Michio; Umemura, Tomonari

    2012-06-15

    In this paper, we describe a method for the preparation of easy-to-use reversed-phase monolithic microbore columns. Polyetheretherketone (PEEK) tubing with an outer diameter of 1/16″ and an inner diameter of 1.0 mm was used as a column housing (empty column), and in it lauryl methacrylate (LMA) was copolymerized with ethylene dimethacrylate (EDMA). In order to chemically anchor the polymer monolith to the tube wall, the inner wall surface was pretreated by the following two-step procedure. (1) 50% sulfuric acid was filled into the PEEK tubing and left to stand for 6 h to generate sulfonate groups on the surface. (2) After washing with Milli-Q water, the sulfonated PEEK surface was brought into contact with 1 M glycidyl methacrylate in dichloromethane (or acetone) at 40°C for 4 h to introduce methacryloyl groups via the reaction of sulfonate groups and epoxy groups. Mechanical strength and column efficiency of the resulting monoliths were evaluated through the separation of a series of alkylbenzenes in acetonitrile-water (50:50, v/v) eluent over the flow rate range of 50-750 μL/min (corresponding to 1.7-25.5 mm/s). The poly(LMA-co-EDMA) monolith provided acceptable column efficiency of 2000 theoretical plates/10 cm (HETP value of 50 μm) for amylbenzene (separation factor k=40) and low flow resistance of 0.5 MPa/10 cm at a normal flow rate of 50 μL/min. The methacryloylated PEEK tubing tightly held the monolith, and the monolithic column exhibited good pressure resistance up to 15 MPa, allowing rapid separation at a 15-20 fold higher flow rate than normal. PMID:22560348

  2. Effective and reusable monolith capillary trap of nitrosamine extraction by superheated water from frankfurter sausage.

    PubMed

    Chienthavorn, Orapin; Ramnut, Narumol; Subprasert, Panee; Sasook, Anupop; Insuan, Wimonrut

    2014-02-12

    A novel, simple, rapid, and inexpensive method of extraction and cleanup of nitrosamines from frankfurter sausage was achieved with a capillary filled with monolith of either polystyrene-co-divinylbenzene (PS-DVB), Polydivinylbenzene (P-DVB), or silica that had been fabricated. The study of capability in trapping nonpolar matrix and monolith capillaries with varied lengths revealed that a silica monolith gave the best result for nitrosamine determination. With an online coupling between superheated water extraction (SWE) and silica monolith capillary connected to a 5% phenyl-methylpolysiloxane column, factors affecting the extraction and determination, namely, sensitivity with and without the monolith, reusability, injection-injection repeatability, capillary-capillary precision, and chromatographic separation, were investigated. This confirmed the feasibility of the method. The optimal length of silica monolith capillary was 30 mm, offering reuse more than 20 times. Separation and quantification of selected volatile nitrosamines were carried out using gas chromatography (GC) coupled with either a flame ionization detector (FID) or mass spectrometer (MS). The overall extraction and determination method determined by GC-MS allowed for a recovery of 75-88% with a <5% relative standard deviation (RSD) and detection limit of 2-5 ng of injected nitrosamine.

  3. [Modification of sol-gel hybrid monolith and its application in determination of polycyclic aromatic hydrocarbons].

    PubMed

    Yang, Rancun; Zhang, Shaowen; Sun, Yu'an

    2015-05-01

    A C6-silica hybrid monolithic column was prepared by click reaction with capillary silica monolith. Firstly, an azide-functionalized silica monolithic column was synthesized via sol-gel reaction with tetramethoxysilane (TMOS) and 3-azidopropyltrimethoxysilane (N3PTMS). Then 1-hexyne was covalently immobilized on the capillary monolith by the "azide-alkyne" click reaction to form C6-silica hybrid monolithic column. As an extraction media of polycyclic aromatic hydrocarbons (PAHs), the conditions for the preparation and modification of the monolith were carefully investigated according to the extraction efficiency. The enrichment factors for typical PAHs: naphthalene, phenanthrene, pyrene and benzo a pyrene finally reached 95.9, 14.2, 103.2 and 57.8, respectively. The relative standard deviations (RSDs) for the extraction were lower than 5.5% (intra-day, t = 8) and 7.3% (inter-day, n = 10). Based on the in-tube solid phase microextraction (in-tube SPME), a new determination method for 16 PAHs was developed with high performance liquid chromatography (HPLC). The limits of detection (LODs, SN = 3) were 0.08-3.72 µg/L and the limits of quantification (LOQs, S/N = 10) were 0.26-12.40 µg/L for the PAHs. The spiked recoveries for the PAHs in soil samples were between 82.4% and 110.6% with the RSDs (n = 3) of 2.6%-7.9%. Comparison with the method of United States Environmental Protection Agency (U. S. EPA) for the PAIs determination in soil samples, the results showed good accuracy and high consistency. And the high extraction efficiency with high sensitivity and convenience was also demonstrated in the applications of the new approach.

  4. Monolithic fiber optic sensor assembly

    SciTech Connect

    Sanders, Scott

    2015-02-10

    A remote sensor element for spectrographic measurements employs a monolithic assembly of one or two fiber optics to two optical elements separated by a supporting structure to allow the flow of gases or particulates therebetween. In a preferred embodiment, the sensor element components are fused ceramic to resist high temperatures and failure from large temperature changes.

  5. Formation of bimodal porous silica-titania monoliths by sol-gel route

    NASA Astrophysics Data System (ADS)

    Ruzimuradov, O. N.

    2011-10-01

    Silica-titania monoliths with micrometer-scale macroporous and nanometer-scale mesoporous structure and high titania contents are prepared by sol-gel process and phase separation. Titanium alkoxide precursor was not effective in the preparation of high titania content composites because of strong decrease in phase separation tendency. Bimodal porous gels with high titania content were obtained by using inorganic salt precursors such as titanium sulfate and titanium chloride. Various characterization techniques, including SEM, XRD, Hg porosimetry and N2 adsorption have been carried out to investigate the formation process and physical-chemical properties of silica-titania monoliths. The characterization results show that the silica-titania monoliths possess a bimodal porous structure with well-dispersed titania inside silica network. The addition of titania in silica improves the thermal stability of both macroporous and mesoporous structures.

  6. Robust monolithic silica-based on-chip electro-osmotic micro-pump.

    PubMed

    Nie, Fu-Qiang; Macka, Mirek; Barron, Leon; Connolly, Damian; Kent, Nigel; Paull, Brett

    2007-05-01

    A robust, compact, on-chip, electro-osmotic micro-pump (EOP) for micro-flow analysis, based on parallel, encased, 10 x 0.1 mm I.D. monolithic silica capillary columns has been developed. A 15 x 40 x 2 mm poly(methyl methacrylate) (PMMA) chip, containing a total of nine parallel EOP systems was fabricated, allowing the use of single, double or triple monolithic columns to produce increased flow as required. The monolithic silica was compatible with both aqueous and organic solvents without swelling or shrinking problems, with the triple column EOP capable of generating flow of up to 0.6 microL min(-1) under zero pressure load and over 0.1 microL min(-1) with an applied pressure of ca. 2.4 bar using an applied voltage of just 2 kV. Current generated at the 2 kV applied voltage for a 2 mM acetate buffer solution (pH 4.5) was under 4 microA, allowing stable, bubble-free flow. The developed triple column EOP was incorporated within a micro-fluidic chip (5.0 x 2.0 x 0.4 cm) integrated with a second single 10 x 0.1 mm column EOP, for combined sample injection and simple on-chip micro-flow analysis.

  7. Irreversible gettering of thionyl chloride

    SciTech Connect

    LeRoy Whinnery; Steve Goods; George Buffleben; Tim Sheppodd

    1999-11-01

    The authors have successfully demonstrated the irreversible gettering of SOCl{sub 2} by ZnO/ASZMTEDA carbon over a modest temperature range. While thionyl chloride decomposition was slow below {minus}20 C, lower temperatures are expected to be less of a problem than at higher temperatures. The approximately 30 cc of thionyl chloride in a typical D-cell would require 50 g of ZnO and 107 g of ASZMTEDA carbon. Fortunately, since it is unlikely to happen at all, it is common practice to assume only one cell will fail (leak) in a given battery pack. So, one charge of getter can protect the whole battery pack. In summary, ZnO/ASZMTEDA carbon fulfills all of the requirements of an ideal getter including: irreversible binding or reaction with SOCl{sub 2}, high volumetric uptake capacity, high efficiency, non-volatile, air stable, insensitive to poisoning, non-toxic, cheap, non-corrosive, and the gettering product is not a liquid or oil that could block further flow or accessibility. Future work in this area includes incorporation of the ZnO and carbon into a structural open-celled porous monolith, as well as, gettering for other types of batteries (e.g., Li/MnO{sub 2}).

  8. Protective Skins for Aerogel Monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Johnston, James C.; Kuczmarski, Maria A.; Meador, Ann B.

    2007-01-01

    A method of imparting relatively hard protective outer skins to aerogel monoliths has been developed. Even more than aerogel beads, aerogel monoliths are attractive as thermal-insulation materials, but the commercial utilization of aerogel monoliths in thermal-insulation panels has been inhibited by their fragility and the consequent difficulty of handling them. Therefore, there is a need to afford sufficient protection to aerogel monoliths to facilitate handling, without compromising the attractive bulk properties (low density, high porosity, low thermal conductivity, high surface area, and low permittivity) of aerogel materials. The present method was devised to satisfy this need. The essence of the present method is to coat an aerogel monolith with an outer polymeric skin, by painting or spraying. Apparently, the reason spraying and painting were not attempted until now is that it is well known in the aerogel industry that aerogels collapse in contact with liquids. In the present method, one prevents such collapse through the proper choice of coating liquid and process conditions: In particular, one uses a viscous polymer precursor liquid and (a) carefully controls the amount of liquid applied and/or (b) causes the liquid to become cured to the desired hard polymeric layer rapidly enough that there is not sufficient time for the liquid to percolate into the aerogel bulk. The method has been demonstrated by use of isocyanates, which, upon exposure to atmospheric moisture, become cured to polyurethane/polyurea-type coats. The method has also been demonstrated by use of commercial epoxy resins. The method could also be implemented by use of a variety of other resins, including polyimide precursors (for forming high-temperature-resistant protective skins) or perfluorinated monomers (for forming coats that impart hydrophobicity and some increase in strength).

  9. Optimization of poly(methyl styrene-co-bis(p-vinylbenzyl)dimethylsilane)-based capillary monoliths for separation of low, medium, and high molecular-weight analytes.

    PubMed

    Lubbad, Said H

    2016-04-22

    Poly(methyl styrene-co-bis(p-vinylbenzyl)dimethylsilane)-based monolithic capillary columns were optimized for separation of low, medium, and high molecular-weight analytes. The morphology and consequently the chromatographic performance of these monoliths were tuned by changes in the volume-ratio of monomer to macroporogen, establishing good monolithic flow-through and retention pores. Two monoliths were prepared and analyzed by reversed-phase chromatographic separation of low molecular-weight analytes such as alkyl benzenes and β-blockers, as well as medium and high molecular-weight analytes such as peptides and proteins, respectively. The microstructure was studied by scanning electron microscopy (SEM), and by inverse-size exclusion chromatography (ISEC). Monolith 1 demonstrated a high retention of alkyl benzenes, which coeluted from the column at the washing step of absolute acetonitrile; yet this monolith established a baseline separation of 9-peptide and 8-protein mixtures. Monolith 2 demonstrated efficient separation of the three analyte groups of different molecular weights. Six alkyl benzenes and five β-blockers were base-line separated in less than 5 and 2min, respectively, with good resolution and very small values of peak width at half height. Moreover, a comparable performance of efficient separation of the 9-peptide mixture and a fast separation of 5- and 8-protein mixtures were achieved. Both monoliths were characterized by high mechanical strength, high permeability, and excellent reproducibility. PMID:27016117

  10. Optimization of poly(methyl styrene-co-bis(p-vinylbenzyl)dimethylsilane)-based capillary monoliths for separation of low, medium, and high molecular-weight analytes.

    PubMed

    Lubbad, Said H

    2016-04-22

    Poly(methyl styrene-co-bis(p-vinylbenzyl)dimethylsilane)-based monolithic capillary columns were optimized for separation of low, medium, and high molecular-weight analytes. The morphology and consequently the chromatographic performance of these monoliths were tuned by changes in the volume-ratio of monomer to macroporogen, establishing good monolithic flow-through and retention pores. Two monoliths were prepared and analyzed by reversed-phase chromatographic separation of low molecular-weight analytes such as alkyl benzenes and β-blockers, as well as medium and high molecular-weight analytes such as peptides and proteins, respectively. The microstructure was studied by scanning electron microscopy (SEM), and by inverse-size exclusion chromatography (ISEC). Monolith 1 demonstrated a high retention of alkyl benzenes, which coeluted from the column at the washing step of absolute acetonitrile; yet this monolith established a baseline separation of 9-peptide and 8-protein mixtures. Monolith 2 demonstrated efficient separation of the three analyte groups of different molecular weights. Six alkyl benzenes and five β-blockers were base-line separated in less than 5 and 2min, respectively, with good resolution and very small values of peak width at half height. Moreover, a comparable performance of efficient separation of the 9-peptide mixture and a fast separation of 5- and 8-protein mixtures were achieved. Both monoliths were characterized by high mechanical strength, high permeability, and excellent reproducibility.

  11. Preparation of organic-inorganic hybrid silica monolith with octyl and sulfonic acid groups for capillary electrochromatograhpy and application in determination of theophylline and caffeine in beverage.

    PubMed

    Chen, Ming-Luan; Zheng, Ming-Ming; Feng, Yu-Qi

    2010-05-21

    An organic-inorganic hybrid silica monolithic column with octyl and sulfonic acid groups has been prepared by sol-gel technique for capillary electrochromatograhpy. The structure of hybrid monolith was optimized by changing the composition of tetraethoxysilane (TEOS), octyltriethoxysilane (C(8)-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) in the mixture of precursors. Then, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups. The sulfonic acid group, which served as strong cation-exchanger, dominated the charge on the surface of the capillary column and generated stable electroosmotic flow (EOF) in a wide range of pH. The monolithic column was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and elemental analysis (EA), and the performance of column was evaluated in detail by separating different kinds of compounds with column efficiency up to 155,000 plates/m for thiourea. In addition, this monolithic column was also applied in the analysis of theophylline (TP) and caffeine (CA) in beverages. The detection limits were 0.39 and 0.48 microg/mL for theophylline and caffeine, respectively. The method reproducibility was tested by evaluating the intra- and inter-day precisions, and relative standard deviations of less than 3.9 and 8.4%, respectively, were obtained. Recoveries of compounds from spiked beverage samples ranged from 87.2 to 105.2%.

  12. One-pot preparation of glutathione-silica hybrid monolith for mixed-mode capillary liquid chromatography based on "thiol-ene" click chemistry.

    PubMed

    Lin, Zian; Tan, Xiaoqing; Yu, Ruifang; Lin, Jiashi; Yin, Xiaofei; Zhang, Lan; Yang, Huanghao

    2014-08-15

    A novel glutathione (GSH)-silica hybrid monolithic column synthesized via a combination of thiol-ene click reaction and one-pot process was described, where thiol-end GSH organic monomer and 2,2-azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethyloxysilane (TMOS) and γ-methacryloxypropyltrimethoxysilane (γ-MAPS) and then introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the GSH-silica hybrid monolith. The effects of the molar ratio of TMOS/γ-MAPS, the amount of GSH, and the volume of porogen on the morphology, permeability and pore properties of the prepared GSH-silica hybrid monoliths were studied in detail. A uniform monolithic network with high porosity was obtained. A series of test compounds including alkylbenzenes, amides, and anilines were used to evaluate the retention behaviors of the GSH-silica hybrid monolithic column. The results demonstrated that the prepared GSH-silica hybrid monolith exhibited multiple interactions including hydrophobicity, hydrophilicity, as well as cation exchange interaction. The run-to-run, column-to-column and batch-to-batch reproducibilities of the GSH-silica hybrid monolith for phenols' retention were satisfactory with the relative standard deviations (RSDs) less than 1.3% (n=5), 2.6% (n=3) and 3.2% (n=3), respectively, indicating the effectiveness and practicability of the proposed method. In addition, the GSH-silica hybrid monolith was applied to the separation of nucleotides, peptides and protein tryptic digests, respectively. The successful applications suggested the potential of the GSH-silica hybrid monolith in complex sample analysis.

  13. 3D printed metal columns for capillary liquid chromatography.

    PubMed

    Sandron, S; Heery, B; Gupta, V; Collins, D A; Nesterenko, E P; Nesterenko, P N; Talebi, M; Beirne, S; Thompson, F; Wallace, G G; Brabazon, D; Regan, F; Paull, B

    2014-12-21

    Coiled planar capillary chromatography columns (0.9 mm I.D. × 60 cm L) were 3D printed in stainless steel (316L), and titanium (Ti-6Al-4V) alloys (external dimensions of ~5 × 30 × 58 mm), and either slurry packed with various sized reversed-phase octadecylsilica particles, or filled with an in situ prepared methacrylate based monolith. Coiled printed columns were coupled directly with 30 × 30 mm Peltier thermoelectric direct contact heater/cooler modules. Preliminary results show the potential of using such 3D printed columns in future portable chromatographic devices. PMID:25285334

  14. Preparation of graphene oxide-modified affinity capillary monoliths based on three types of amino donor for chiral separation and proteolysis.

    PubMed

    Hong, Tingting; Chen, Xueping; Xu, Yujing; Cui, Xiaoqin; Bai, Ruihan; Jin, Can; Li, Ruijun; Ji, Yibing

    2016-07-22

    Novel graphene oxide (GO)-modified affinity capillary monoliths were developed employing human serum albumin (HSA) or pepsin as chiral selector. Three types of amino donors for GO immobilization, including ammonium hydroxide (NH4OH), ethanediamine (EDA) and polyethyleneimine (PEI), were applied to explore the effect of spacer arm on enantioseparation. It was observed that HSA-GO-EDA-based affinity capillary monoliths exhibited better chiral recognition ability in comparison with the other two spacer-based monoliths. Under the optimized conditions, the obtained columns revealed satisfactory repeatability concerning column-to-column, run-to-run and interday repeatability. In addition, the impact of GO concentration on enantiomeric separation was also investigated. HSA-GO-EDA-based affinity capillary monoliths provided higher chiral selectivity for nine pairs of enantiomers compared to the columns without GO. Furthermore, the influence of amino donors and GO on proteolytic activity of pepsin-based immobilized enzymatic reactor (IMER) was discussed. Unfortunately, pepsin-GO-PEI-based affinity capillary monoliths possessed the highest protein digestion capacity, which was different from the effect of amino donors on enantiorecognition. Moreover, GO presented as a favorable choice to improve the enzymatic activity of IMER. These results proved that GO-functionalized affinity capillary monoliths have promising potential for chiral separation and proteolysis.

  15. Fast preparation of a highly efficient organic monolith via photo-initiated thiol-ene click polymerization for capillary liquid chromatography.

    PubMed

    Chen, Lianfang; Ou, Junjie; Liu, Zhongshan; Lin, Hui; Wang, Hongwei; Dong, Jing; Zou, Hanfa

    2015-05-15

    A novel organic monolith was firstly prepared in a UV-transparent fused-silica capillary by a single-step approach via photo-initiated thiol-ene click polymerization reaction of 1,2,4-trivinylcyclohexane (TVCH) and pentaerythriol tetra(3-mercaptopropionate) (4SH) within 10min. The effects of both composition of prepolymerization solution and polymerization time on the morphology and permeability of monolithic column were investigated in detail. Then, the optimal condition was acquired to fabricate a homogeneous and permeable organic monolith. The chemical groups of the monolithic column were confirmed by Fourier transform infrared spectroscopy (FT-IR). The SEM graphs showed the organic monolith possessed a uniform porous structure, which promotes the highest column efficiency of ∼133,000 plates per meter for alkylbenzenes at the linear velocity of 0.65mm/s in reversed-phase liquid chromatography. Finally, the organic monolithic column was further applied for separation of basic compounds, pesticides and EPA610, indicating satisfactory separation ability.

  16. Preparation of graphene oxide-modified affinity capillary monoliths based on three types of amino donor for chiral separation and proteolysis.

    PubMed

    Hong, Tingting; Chen, Xueping; Xu, Yujing; Cui, Xiaoqin; Bai, Ruihan; Jin, Can; Li, Ruijun; Ji, Yibing

    2016-07-22

    Novel graphene oxide (GO)-modified affinity capillary monoliths were developed employing human serum albumin (HSA) or pepsin as chiral selector. Three types of amino donors for GO immobilization, including ammonium hydroxide (NH4OH), ethanediamine (EDA) and polyethyleneimine (PEI), were applied to explore the effect of spacer arm on enantioseparation. It was observed that HSA-GO-EDA-based affinity capillary monoliths exhibited better chiral recognition ability in comparison with the other two spacer-based monoliths. Under the optimized conditions, the obtained columns revealed satisfactory repeatability concerning column-to-column, run-to-run and interday repeatability. In addition, the impact of GO concentration on enantiomeric separation was also investigated. HSA-GO-EDA-based affinity capillary monoliths provided higher chiral selectivity for nine pairs of enantiomers compared to the columns without GO. Furthermore, the influence of amino donors and GO on proteolytic activity of pepsin-based immobilized enzymatic reactor (IMER) was discussed. Unfortunately, pepsin-GO-PEI-based affinity capillary monoliths possessed the highest protein digestion capacity, which was different from the effect of amino donors on enantiorecognition. Moreover, GO presented as a favorable choice to improve the enzymatic activity of IMER. These results proved that GO-functionalized affinity capillary monoliths have promising potential for chiral separation and proteolysis. PMID:27334417

  17. Monolithic-integrated microlaser encoder.

    PubMed

    Sawada, R; Higurashi, E; Ito, T; Ohguchi, O; Tsubamoto, M

    1999-11-20

    We have developed an extremely small integrated microencoder whose sides are less than 1 mm long. It is 1/100 the size of conventional encoders. This microencoder consists of a laser diode, monolithic photodiodes, and fluorinated polyimide waveguides with total internal reflection mirrors. The instrument can measure the relative displacement between a grating scale and the encoder with a resolution of the order of 0.01 microm; it can also determine the direction in which the scale is moving. By using the two beams that were emitted from the two etched mirrors of the laser diode, by monolithic integration of the waveguide and photodiodes, and by fabrication of a step at the edge of the waveguide, we were able to eliminate conventional bulky optical components such as the beam splitter, the quarter-wavelength plate, bulky mirrors, and bulky photodetectors. PMID:18324228

  18. Aptamer-based organic-silica hybrid affinity monolith prepared via "thiol-ene" click reaction for extraction of thrombin.

    PubMed

    Wang, Zheng; Zhao, Jin-cheng; Lian, Hong-zhen; Chen, Hong-yuan

    2015-06-01

    A novel strategy for preparing aptamer-based organic-silica hybrid monolithic column was developed via "thiol-ene" click chemistry. Due to the large specific surface area of the hybrid matrix and the simplicity, rapidness and high efficiency of "thiol-ene" click reaction, the average coverage density of aptamer on the organic-silica hybrid monolith reached 420 pmol μL(-1). Human α-thrombin can be captured on the prepared affinity monolithic column with high specificity and eluted by NaClO4 solution. N-p-tosyl-Gly-Pro-Arg p-nitroanilide acetate was used as the sensitive chromogenic substrate of thrombin. The thrombin enriched by this affinity column was detected with a detection of limit of 0.01 μM by spectrophotometry. Furthermore, the extraction recovery of thrombin at 0.15 μM in human serum was 91.8% with a relative standard deviation of 4.0%. These results indicated that "thiol-ene" click chemistry provided a promising technique to immobilize aptamer on organic-inorganic hybrid monolith and the easily-assembled affinity monolithic material could be used to realize highly selective recognition of trace proteins.

  19. Peptide immobilized monolith containing tentacle-type functionalized polymer chains for high-capacity binding of immunoglobulin G.

    PubMed

    Du, Kaifeng

    2014-12-29

    A peptide immobilized tentacle-type monolith is developed here for high-performance IgG purification. In this work, the glucose-anchored GMA molecules serve as monomers to be grafted into the tentacle-type chains on highly porous monolith by a series of chemical reactions. While maintaining high column permeability, the tentacle grafting endows the monolith with lots of reactive handles to anchor more peptides. With that, the grafted monolith shows high peptide density of about 155μmolmL(-1), up to approximately 4.7 times higher over the ungrafted one (33μmolmL(-1)). As a result, the static adsorbing capacity and dynamic adsorption capacity at 50% breakthrough point reach 101.8 and 83.3mgmL(-1) for IgG adsorption, respectively. Regeneration, recycle and reuse of grafted monolith are highly successful for 25 runs without obvious capacity loss. By taking these advantages of high capacity and excellent structure stability, the affinity grafted monolith is evaluated by using cleared human blood supernatant. And the result shows the peptide immobilized tentacle type monolith displays excellent specificity and high effectiveness for IgG purification.

  20. Peptide immobilized monolith containing tentacle-type functionalized polymer chains for high-capacity binding of immunoglobulin G.

    PubMed

    Du, Kaifeng

    2014-12-29

    A peptide immobilized tentacle-type monolith is developed here for high-performance IgG purification. In this work, the glucose-anchored GMA molecules serve as monomers to be grafted into the tentacle-type chains on highly porous monolith by a series of chemical reactions. While maintaining high column permeability, the tentacle grafting endows the monolith with lots of reactive handles to anchor more peptides. With that, the grafted monolith shows high peptide density of about 155μmolmL(-1), up to approximately 4.7 times higher over the ungrafted one (33μmolmL(-1)). As a result, the static adsorbing capacity and dynamic adsorption capacity at 50% breakthrough point reach 101.8 and 83.3mgmL(-1) for IgG adsorption, respectively. Regeneration, recycle and reuse of grafted monolith are highly successful for 25 runs without obvious capacity loss. By taking these advantages of high capacity and excellent structure stability, the affinity grafted monolith is evaluated by using cleared human blood supernatant. And the result shows the peptide immobilized tentacle type monolith displays excellent specificity and high effectiveness for IgG purification. PMID:25476688

  1. Influence of porogen nature on the kinetic and potential efficiencies of divinylbenzene-based monolithic sorbents in gas chromatography

    NASA Astrophysics Data System (ADS)

    Korolev, A. A.; Shiryaeva, V. E.; Popova, T. P.; Kanat'eva, A. Yu.; Kurganov, A. A.

    2015-02-01

    It has been shown that using Poppe curves for characterization of monolithic sorbents makes it possible to optimize conditions for both the synthesis of monoliths intended for high-speed analysis and achievement of the best separation efficiency. The influence of the nature of a porogen on the kinetic efficiency of monolithic sorbents in high-pressure gas chromatography has been considered. It has been found that the nature of the porogen alcohol determines to a considerable extent the structure of the monolith and its kinetic efficiency. The sorbents prepared with the use of octanol-1 and dodecanol-1 have shown the best kinetic characteristics; however, minimal HETP values have been observed for the columns prepared using hexanol-1 as a porogen.

  2. Monolithic pattern-sensitive detector

    DOEpatents

    Berger, Kurt W.

    2000-01-01

    Extreme ultraviolet light (EUV) is detected using a precisely defined reference pattern formed over a shallow junction photodiode. The reference pattern is formed in an EUV absorber preferably comprising nickel or other material having EUV- and other spectral region attenuating characteristics. An EUV-transmissive energy filter is disposed between a passivation oxide layer of the photodiode and the EUV transmissive energy filter. The device is monolithically formed to provide robustness and compactness.

  3. Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

    PubMed

    Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

    2015-06-01

    An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography.

  4. Solution-Derived, Chloride-Containing Minerals as a Waste Form for Alkali Chlorides

    SciTech Connect

    Riley, Brian J.; Crum, Jarrod V.; Matyas, Josef; McCloy, John S.; Lepry, William C.

    2012-10-01

    Sodalite [Na8(AlSiO4)6Cl2] and cancrinite [(Na,K)6Ca2Al6Si6O24Cl4] are environmentally stable, chloride-containing minerals and are a logical waste form option for the mixed alkali chloride salt waste stream that is generated from a proposed electrochemical separations process during nuclear fuel reprocessing. Due to the volatility of chloride salts at moderate temperatures, the ideal processing route for these salts is a low-temperature approach such as the sol-gel process. The sodalite structure can be easily synthesized by the sol-gel process; however, it is produced in the form of a fine powder with particle sizes on the order of 1–10 µm. Due to the small particle size, these powders require additional treatment to form a monolith. In this study, the sol-gel powders were pressed into pellets and fired to achieve > 90% of theoretical density. The cancrinite structure, identified as the best candidate mineral form in terms of waste loading capacity, was only produced on a limited basis following the sol-gel process and converted to sodalite upon firing. Here we discuss the sol-gel process specifics, chemical durability of select waste forms, and the steps taken to maximize chloride-containing phases, decrease chloride loss during pellet firing, and increase pellet densities.

  5. Characterization of polymer monoliths containing embedded nanoparticles by scanning transmission X-ray microscopy (STXM).

    PubMed

    Arrua, R Dario; Hitchcock, Adam P; Hon, Wei Boon; West, Marcia; Hilder, Emily F

    2014-03-18

    The structural and chemical homogeneity of monolithic columns is a key parameter for high efficiency stationary phases in liquid chromatography. Improved characterization techniques are needed to better understand the polymer morphology and its optimization. Here the analysis of polymer monoliths by scanning transmission X-ray microscopy (STXM) is presented for the first time. Poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) [poly(BuMA-co-EDMA)] monoliths containing encapsulated divinylbenzene (DVB) nanoparticles were characterized by STXM, which gives a comprehensive, quantitative chemical analysis of the monolith at a spatial resolution of 30 nm. The results are compared with other methods commonly used for the characterization of polymer monoliths [scanning electron microscopy (SEM), transmission electron microscopy (TEM), mercury porosimetry, and nitrogen adsorption]. The technique permitted chemical identification and mapping of the nanoparticles within the polymeric scaffold. Residual surfactant, which was used during the manufacture of the nanoparticles, was also detected. We show that STXM can give more in-depth chemical information for these types of materials and therefore lead to a better understanding of the link between polymer morphology and chromatographic performance.

  6. Collecting peptide release from the brain using porous polymer monolith-based solid phase extraction capillaries.

    PubMed

    Iannacone, Jamie M; Ren, Shifang; Hatcher, Nathan G; Sweedler, Jonathan V

    2009-07-01

    Porous polymer monolithic (PPM) columns are employed to collect and concentrate neuronal release from invertebrate and vertebrate model systems, prior to their characterization with mass spectrometry. The monoliths are fabricated in fused-silica capillaries from lauryl methacrylate (LMA) and ethylene glycol dimethacrylate (EDMA). The binding capacities for fluorescein and for fluorescently labeled peptides are on the order of nanomoles per millimeter of length of monolith material for a capillary with an inner diameter of 200 microm. To evaluate this strategy for collecting peptides from physiological solutions, angiotensin I and insulin in artificial seawater are loaded onto, and then released from, the monoliths after a desalination rinse, resulting in femtomole limits of detection via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Positioned in the extracellular media near Aplysia californica bag cell neurons, upon electrical stimulation, these LMA-EDMA monoliths are also used to collect and concentrate peptide release, with egg-laying hormones and acidic peptide detected. In addition, the collection of several known peptides secreted from chemically stimulated mouse brain slices demonstrates their ability to collect releasates from a variety of neuronal tissues. When compared to collection approaches using individual beads placed on brain slices, the PPM capillaries offer greater binding capacity. Moreover, they maintain higher spatial resolution, compared to the larger-volume, solid-phase extraction collection strategies.

  7. Characterization of polymer monoliths containing embedded nanoparticles by scanning transmission X-ray microscopy (STXM).

    PubMed

    Arrua, R Dario; Hitchcock, Adam P; Hon, Wei Boon; West, Marcia; Hilder, Emily F

    2014-03-18

    The structural and chemical homogeneity of monolithic columns is a key parameter for high efficiency stationary phases in liquid chromatography. Improved characterization techniques are needed to better understand the polymer morphology and its optimization. Here the analysis of polymer monoliths by scanning transmission X-ray microscopy (STXM) is presented for the first time. Poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) [poly(BuMA-co-EDMA)] monoliths containing encapsulated divinylbenzene (DVB) nanoparticles were characterized by STXM, which gives a comprehensive, quantitative chemical analysis of the monolith at a spatial resolution of 30 nm. The results are compared with other methods commonly used for the characterization of polymer monoliths [scanning electron microscopy (SEM), transmission electron microscopy (TEM), mercury porosimetry, and nitrogen adsorption]. The technique permitted chemical identification and mapping of the nanoparticles within the polymeric scaffold. Residual surfactant, which was used during the manufacture of the nanoparticles, was also detected. We show that STXM can give more in-depth chemical information for these types of materials and therefore lead to a better understanding of the link between polymer morphology and chromatographic performance. PMID:24552424

  8. Synthesis of a reactive polymethacrylate capillary monolith and its use as a starting material for the preparation of a stationary phase for hydrophilic interaction chromatography.

    PubMed

    Kip, Çiğdem; Erkakan, Damla; Gökaltun, Aslıhan; Çelebi, Bekir; Tuncel, Ali

    2015-05-29

    Poly(3-chloro-2-hydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(HPMA-Cl-co-EDMA) capillary monolith was proposed as a reactive starting material with tailoring flexibility for the preparation of monolithic stationary phases. The reactive capillary monolith was synthesized by free radical copolymerization of 3-chloro-2-hydroxypropyl methacrylate (HPMA-Cl) and ethylene dimethacrylate (EDMA). The mean pore size, the specific surface area and the permeability of poly(HPMA-Cl-co-EDMA) monoliths were controlled by adjusting porogen/monomer volume ratio, porogen composition and polymerization temperature. The porogen/monomer volume ratio was found as the most effective factor controlling the porous properties of poly(HPMA-Cl-co-EDMA) monolith. Triethanolamine (TEA-OH) functionalized polymethacrylate monoliths were prepared by using the reactive chloropropyl group of poly(HPMA-Cl-co-EDMA) monolith via one-pot and simple post-functionalization process. Poly(HPMA-Cl-co-EDMA) monolith reacted with TEA-OH was evaluated as a stationary phase in nano-hydrophilic interaction chromatography (nano-HILIC). Nucleotides, nucleosides and benzoic acid derivatives were satisfactorily separated with the plate heights up to 20μm. TEA-OH attached-poly(HPMA-Cl-co-EDMA) monolith showed a reproducible and stable retention behaviour in nano-HILIC runs. However, a decrease in the column performance (i.e. an increase in the plate height) was observed with the increasing retention factor. Hence "retention-dependent column efficiency" behaviour was shown for HILIC mode using the chromatographic data collected with the polymer based monolith synthesized.

  9. In situ synthesis of metal-organic frameworks in a porous polymer monolith as the stationary phase for capillary liquid chromatography.

    PubMed

    Yang, Shengchao; Ye, Fanggui; Zhang, Cong; Shen, Shufen; Zhao, Shulin

    2015-04-21

    In this study, HKUST-1 was synthesized in situ on the porous polymer monolith as the stationary phase for capillary liquid chromatography (cLC). The unique carboxyl functionalized poly(methacrylic acid-co-ethylene dimethacrylate) (poly(MAA-co-EDMA)) monolith was used as a support to directly grow HKUST-1 by a controlled layer-by-layer self-assembly strategy. X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectroscopy of the resulting HKUST-1-poly(MAA-co-EDMA) monoliths indicated that HKUST-1 was successfully grafted onto the pore surface of the poly(MAA-co-EDMA) monolith. The column performance of HKUST-1-poly(MAA-co-EDMA) monoliths for the separation of various small molecules, such as benzenediols, xylenes, ethylbenzenes, and styrenes, was evaluated. The chromatographic performance was found to improve with increasing HKUST-1 density, and the column efficiencies and resolutions of HKUST-1-poly(MAA-co-EDMA) monoliths were 18 320-19 890 plates m(-1) and 1.62-6.42, respectively, for benzenediols. The HKUST-1-poly(MAA-co-EDMA) monolith displayed enhanced resolution for the separation of positional isomers when compared to the traditional C18 and HKUST-1 incorporated polymer monoliths. Hydrophobic, π-π, and hydrogen bonding interactions within the HKUST-1-poly(MAA-co-EDMA) monolith were observed in the separation of small molecules. The results showed that the HKUST-1-poly(MAA-co-EDMA) monoliths are promising stationary phases for cLC.

  10. A high boronate avidity monolithic capillary for the selective enrichment of trace glycoproteins.

    PubMed

    Li, Daojin; Li, Yang; Li, Xinglin; Bie, Zijun; Pan, Xianghua; Zhang, Qian; Liu, Zhen

    2015-03-01

    Boronate affinity materials, as effective sample enrichment sorbents for glycoproteomic analysis, have attracted increasing attention in recent years. However, most of boronate affinity materials suffer from an apparent limitation, limited binding strength. As a result, extraction of glycoproteins of trace concentration is rather difficult or impossible. In this study, we present a high boronate avidity monolithic capillary. Branched polyethyleneimine (PEI) was used as a scaffold to amplify the number of boronic acid moieties. While 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA), which exhibited ultrahigh affinity toward cis-diol-containing compounds, was employed as an affinity ligand. Due to the PEI-assisted synergistic multivalent binding, the monolithic column exhibited high boronate avidity toward glycoproteins, with binding constants of 10(-6)-10(-7)M. Such binding strength was the highest among already reported boronic acid-functionalized materials that can be used for glycoproteomic analysis. Besides, the boronate avidity monolithic column exhibited one additional beneficial feature, lowered binding pH (≥6.5). These features greatly favored the selective enrichment of trace glycoproteins from real samples. The feasibility for practical applications was demonstrated with the selective enrichment of trace glycoproteins in human saliva. As compared with other boronate avidity/affinity materials, the boronate avidity monolithic capillary exhibited the best performance.

  11. Aptamer functionalized hydrophilic polymer monolith with gold nanoparticles modification for the sensitive detection of human α-thrombin.

    PubMed

    Chen, Yuanbo; Deng, Nan; Wu, Ci; Liang, Yu; Jiang, Bo; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-07-01

    Low abundant proteins of body fluids participate nearly all physiological processes and indicate various kinds of diseases. The development of specific enrichment techniques is the key to identify and quantify the low abundant proteins. Herein, a novel kind of aptamer functionalized hydrophilic polymer monolith was developed for the specific enrichment and detection of human α-thrombin from the human plasma. Human α-thrombin aptamer, with thiol group modified at the 5' terminal, was immobilized on the gold nanoparticles (AuNPs) modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) monolithic column, with the binding capacity of 277.1μmol/L. Due to the hydrophilic poly(ethylene glycol) diacrylate) as the cross-linking monomer, the detection recovery of the aptamer-functionalized hydrophilic polymer monolithic column could reach to 92.6±5.2% (n=3) and the dynamic range could reach 0.5-300ng/μL (S/N>10) with on-line UV detection. Meanwhile, the column could run over 100 times, because the poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) stability structure and the AuNPs improved the stability of the matrix material. Furthermore, this column could even capture the target α-thrombin, which was spiked in 1000 folds of original human plasma. All these results demonstrated the great potential of the prepared aptamer functionalized hydrophilic polymer monolith for the recognition of the trace proteins in the biological samples. PMID:27154714

  12. Aptamer functionalized hydrophilic polymer monolith with gold nanoparticles modification for the sensitive detection of human α-thrombin.

    PubMed

    Chen, Yuanbo; Deng, Nan; Wu, Ci; Liang, Yu; Jiang, Bo; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-07-01

    Low abundant proteins of body fluids participate nearly all physiological processes and indicate various kinds of diseases. The development of specific enrichment techniques is the key to identify and quantify the low abundant proteins. Herein, a novel kind of aptamer functionalized hydrophilic polymer monolith was developed for the specific enrichment and detection of human α-thrombin from the human plasma. Human α-thrombin aptamer, with thiol group modified at the 5' terminal, was immobilized on the gold nanoparticles (AuNPs) modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) monolithic column, with the binding capacity of 277.1μmol/L. Due to the hydrophilic poly(ethylene glycol) diacrylate) as the cross-linking monomer, the detection recovery of the aptamer-functionalized hydrophilic polymer monolithic column could reach to 92.6±5.2% (n=3) and the dynamic range could reach 0.5-300ng/μL (S/N>10) with on-line UV detection. Meanwhile, the column could run over 100 times, because the poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) stability structure and the AuNPs improved the stability of the matrix material. Furthermore, this column could even capture the target α-thrombin, which was spiked in 1000 folds of original human plasma. All these results demonstrated the great potential of the prepared aptamer functionalized hydrophilic polymer monolith for the recognition of the trace proteins in the biological samples.

  13. Enantioseparation of basic chiral drugs on a carbamoylated erythromycin-zirconia hybrid monolith using capillary electrochromatography.

    PubMed

    Dixit, Shuchi; Park, Jung Hag

    2015-10-16

    An organic-inorganic hybrid monolithic column was prepared within the confines of a capillary via a single-step in situ sol-gel approach using zirconium tetrabutoxide as a precursor to compose the inorganic backbone and 3-triethoxysilylpropyl carbamoylated derivative of erythromycin (TEOSPC-ERY) as a co-precursor to introduce the organic chiral selector moiety in the zirconia backbone. The resulting carbamoylated ERY-zirconia hybrid monolith (ERY-ZHM) showed homogeneous morphology with well-defined through pores and was tightly connected with the inner wall of the capillary. The column was employed for capillary electrochromatographic enantioseparation of six basic chiral drugs in mobile phases (MPs) consisting of acetonitrile (ACN) and triethylammonium acetate (TEAA) buffer. The effects of composition of MP and applied voltage on chiral separation were investigated by using propranolol as a representative analyte. The highest resolution (Rs=3.33) was obtained with a MP consisting of 10/90 (v/v) ACN/TEAA buffer (10mM, pH 7), 10 kV applied voltage and 25°C capillary temperature. The relative standard deviations for resolution values regarding run to run, day to day, column to column and batch to batch repeatability were 0.41%, 0.89%, 1.80% and 2.26% (for n=3), respectively, indicating satisfactory stability of columns and reproducibility of column preparation process.

  14. Synthesis of boronate-silica hybrid affinity monolith via a one-pot process for specific capture of glycoproteins at neutral conditions.

    PubMed

    Yang, F; Mao, J; He, X W; Chen, L X; Zhang, Y K

    2013-08-01

    In this study, a boronate-silica hybrid affinity monolith was prepared for specific capture of glycoproteins at neutral pH condition. The monolith was synthesized via a facile one-pot procedure in a stainless steel column by concurrently mixing hydrolyzed alkoxysilanes tetramethoxysilane and vinyltrimethoxysilane, organic monomer 3-acrylamidophenylboronic acid and initiator 2,2'-azobisisobutyronitrile together. The polycondensation of alkoxysilanes and copolymerization of organic monomer and vinyl-silica monolith were carried out successively by reacting at different temperatures. After optimizing the preparation conditions, the resulting hybrid affinity monolith was systematically characterized and exhibited excellent affinity to both cis-diol-containing small molecules and glycoproteins at neutral and physiological pH, including adenosine, horseradish peroxidase, transferrin and ovalbumin. The binding capacity of ovalbumin on monolith was measured to be 2.5 mg g(-1) at pH 7.0. Furthermore, the hybrid affinity monolith was applied to the separation of transferrin from bovine serum sample at a physiological condition. Good repeatability was obtained and the relative standard deviations of retention time were 1.15 and 4.77 % (n = 5) for run-to-run and column-to-column, respectively. PMID:23807307

  15. Chloride in diet

    MedlinePlus

    ... found in table salt or sea salt as sodium chloride. It is also found in many vegetables. Foods ... Nutrition Board. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academy Press, Washington, DC: 2005. ...

  16. Compact monolithic capacitive discharge unit

    DOEpatents

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  17. Improved monolithic tandem solar cell

    SciTech Connect

    Wanlass, M.W.

    1991-04-23

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surf ace of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.

  18. Nanosecond monolithic CMOS readout cell

    DOEpatents

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  19. Monolithic 20-GHz Transmitting Module

    NASA Technical Reports Server (NTRS)

    Kascak, T.; Kaelin, G.; Gupta, A.

    1986-01-01

    20-GHz monolithic microwave/millimeter-wave integrated circuit (MMIC) with amplification and phase-shift (time-delay) capabilities developed. Use of MMIC module technology promises to make feasible development of weight- and cost-effective phased-array antenna systems, identified as major factor in achieving minimum cost and efficient use of frequency and orbital resources of future generations of communication satellite systems. Use of MMIC transmitting modules provides for relatively simple method for phase-shift control of many separate radio-frequency (RF) signals required for phased-array antenna systems.

  20. Monolithically integrated absolute frequency comb laser system

    DOEpatents

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  1. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  2. Adsorption over polyacrylonitrile based carbon monoliths

    NASA Astrophysics Data System (ADS)

    Nandi, Mahasweta; Dutta, Arghya; Patra, Astam Kumar; Bhaumik, Asim; Uyama, Hiroshi

    2013-02-01

    Highly porous activated carbon monoliths have been prepared from mesoporous polyacrylonitrile (PAN) monolith as the carbon precursor. The mesoporous PAN monoliths are fabricated by a unique and facile template-free method which on carbonization gives N-doped activated carbon monoliths. The carbonization is achieved via two step thermal process which includes pretreatment in air leading to cyclization and subsequent aromatization of the PAN moieties followed by carbonization in a mixture of argon and carbon dioxide to give a layered carbon framework. Nitrogen sorption experiments carried over these carbon monoliths revealed high surface area (ca. 2500 m2g-1) for these materials with precise micropore size distribution. The activated carbons show extraordinarily high CO2 capture capacity and the uptake up to 3 bar has been found to be as high as 22.5 and 10.6 mmol/g at 273 K and 298 K, respectively.

  3. Assessment of dynamic surface leaching of monolithic surface road materials.

    PubMed

    Paulus, Hélène; Schick, Joachim; Poirier, Jean-Eric

    2016-07-01

    Construction materials have to satisfy, among others, health and environment requirements. To check the environmental compatibility of road construction materials, release of hazardous substances into water must be assessed. Literature mostly describes the leaching behaviour of recycled aggregates for potential use in base or sub-base layers of roads. But little is known about the release of soluble substances by materials mixed with binders and compacted for intended use on road surface. In the present study, we thus performed a diffusion test with sequential renewal of water during a 64 day period according to CEN/TS 16637-2 specifications, on asphalt concretes and hydraulically bound monoliths, two common surface road materials. It is shown that release of dangerous substances is limited in these hydrodynamic conditions. It was particularly true for asphalt concrete leachates where no metallic trace element, sulphate, chloride or fluoride ion could be quantified. This is because of the low hydraulic conductivity and the low polarity of the petroleum hydrocarbon binder of these specimens. For hydraulically bound materials around 20,000 mg/m(2) of sulphate diffused from the monoliths. It is one order of magnitude higher than chloride diffusion and two orders of magnitude higher than fluoride release. No metallic trace element, except small quantities of copper in the last eluate could be quantified. No adverse effect is to be expected for human and environmental health from the leachates of these compacted surface road construction materials, because all the measured parameters were below EU (Council Directive 98/83/EC) or WHO guidelines for drinking water standards. PMID:27039367

  4. Microfluidic devices and methods including porous polymer monoliths

    DOEpatents

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  5. Microfluidic devices and methods including porous polymer monoliths

    SciTech Connect

    Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

    2015-12-01

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  6. Enantiomeric separation by capillary electrochromatography on a sulfated poly β-cyclodextrin modified silica-based monolith.

    PubMed

    Yuan, Ruijuan; Wang, Yan; Ding, Guosheng

    2010-01-01

    A sulfated poly β-cyclodextrin (SPCD) modified silica-based monolithic column was prepared for enantiomeric separation. First, 2-hydroxy-3-allyloxy-propyl-β-cyclodextrin (allyl-β-CD) was bonded onto a bifunctional reagent 3-(methacryloxy)propyltriethoxysilane (γ-MAPS) modified silica-based monolith through radical polymerization; the column was then sulfated with chlorosulfonic acid. The SPCD chiral stationary phase resolved the boring problem associated with desalting when sulfated CDs were synthesized to act as chiral additives. The inorganic salt in the column introduced during the sulfating process could be easily removed by washing the column with water for some time. Chiral compounds investigated were successfully resolved into their enantiomers on the SPCD modified monolith in the capillary electrochromatography (CEC) mode. Due to the existence of the -SO(3)H group, electrosmotic flow (EOF) was obviously increased, and all of the separations could be carried out in 20 min with only a minor loss in the column efficiency and resolution. PMID:20834124

  7. Catalyst assisted synthesis of initiator attached silica monolith particles via isocyanate-hydroxyl reaction for production of polystyrene bound chromatographic stationary phase of excellent separation efficiency.

    PubMed

    Ali, Faiz; Kim, Yune Sung; Lee, Jin Wook; Cheong, Won Jo

    2014-01-10

    Dibutyltin dichloride (DBTDC) was used as a catalyst to chemically bind 4-chloromehtylphenylisocynate (4-CPI) to porous monolithic silica particles via isocyanate-hydroxyl reaction, and the reaction product was reacted with sodium diethyldithiocarbamate (SDDC) to yield initiator attached silica monolith particles. Reversible addition-fragmentation transfer (RAFT) polymerization was taken place on them to result in polystyrene attached silica particles that showed excellent separation efficiency when packed in a chromatographic column (1.0 mm × 300 mm). The numbers of theoretical plates (N) of 56,500 is better than those of any commercially available HPLC or UHPLC column yet.

  8. A weak cation-exchange monolith as stationary phase for the separation of peptide diastereomers by CEC.

    PubMed

    Ludewig, Ronny; Nietzsche, Sandor; Scriba, Gerhard K E

    2011-01-01

    A CEC weak cation-exchange monolith has been prepared by in situ polymerization of acrylamide, methylenebisacrylamide and 4-acrylamidobutyric acid in a decanol-dimethylsulfoxide mixture as porogen. The columns were evaluated by SEM and characterized with regard to the separation of diastereomers and α/β-isomers of aspartyl peptides. Column preparation was reproducible as evidenced by comparison of the analyte retention times of several columns prepared simultaneously. Analyte separation was achieved using mobile phases consisting of acidic phosphate buffer and ACN. Under these conditions the peptides migrated due to their electrophoretic mobility but the EOF also contributed as driving force as a function of the pH of the mobile phase due to increasing dissociation of the carboxyl groups of the polymer. Raising the pH of the mobile phase also resulted in deprotonation of the peptides reducing analyte mobility. Due to these mechanisms each pair of diastereomeric peptides displayed the highest resolution at a different pH of the buffer component of the mobile phase. Comparing the weak-cation exchange monolith to an RP monolith and a strong cation-exchange monolith different elution order of some peptide diastereomers was observed, clearly illustrating that interactions with the stationary phase contribute to the CEC separations.

  9. Monolithic solid electrolyte oxygen pump

    DOEpatents

    Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

    1989-01-01

    A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

  10. Monolithic Continuous-Flow Bioreactors

    NASA Technical Reports Server (NTRS)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  11. Minicircle DNA purification using a CIM® DEAE-1 monolithic support.

    PubMed

    Diamantino, Tatiana; Pereira, Patrícia; Queiroz, João A; Sousa, Ângela; Sousa, Fani

    2016-09-01

    Minicircle DNA is a new biotechnological product with beneficial therapeutic perspectives for gene therapy because it is constituted only by the eukaryotic transcription unit. These features improve minicircle DNA safety and increase its therapeutic effect. However, being a recently developed product, there is a need to establish efficient purification methodologies, enabling the recovery of the supercoiled minicircle DNA isoform. Thus, this work describes the minicircle DNA purification using an anion exchange monolithic support. The results show that with this column it is possible to achieve a good selectivity, which allows the isolation of the supercoiled minicircle DNA isoform from impurities. Overall, this study shows a promising approach to obtain the minicircle DNA sample with adequate quality for future therapeutic applications. PMID:27600622

  12. Anisotropically structured magnetic aerogel monoliths

    NASA Astrophysics Data System (ADS)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and

  13. Monolithic cells for solar fuels.

    PubMed

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

    2014-12-01

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed.

  14. Activated carbon monoliths for methane storage

    NASA Astrophysics Data System (ADS)

    Chada, Nagaraju; Romanos, Jimmy; Hilton, Ramsey; Suppes, Galen; Burress, Jacob; Pfeifer, Peter

    2012-02-01

    The use of adsorbent storage media for natural gas (methane) vehicles allows for the use of non-cylindrical tanks due to the decreased pressure at which the natural gas is stored. The use of carbon powder as a storage material allows for a high mass of methane stored for mass of sample, but at the cost of the tank volume. Densified carbon monoliths, however, allow for the mass of methane for volume of tank to be optimized. In this work, different activated carbon monoliths have been produced using a polymeric binder, with various synthesis parameters. The methane storage was studied using a home-built, dosing-type instrument. A monolith with optimal parameters has been fabricated. The gravimetric excess adsorption for the optimized monolith was found to be 161 g methane for kg carbon.

  15. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  16. Preparation of a thermoresponsive polymer grafted polystyrene monolithic capillary for the separation of bioactive compounds.

    PubMed

    Koriyama, Takuya; Asoh, Taka-Aki; Kikuchi, Akihiko

    2016-11-01

    To develop aqueous microseparation columns for bioactive compounds, a thermoresponsive polymer grafted polymer monolith was prepared inside silica capillaries having an I.D. of 100μm by polymerization of styrene (St) with m/p-divinylbenzene (DVB) in the presence of polydimethylsiloxane as porogen, followed by surface-initiated atom transfer radical polymerization (SI-ATRP) of N-isopropylacrylamide (NIPAAm). SEM analysis indicated that the resulting poly(N-isopropylacrylamide) (PNIPAAm) grafted polystyrene monolith had a consecutive three-dimensionally interconnected structure and through-pores, similar to the base polystyrene (PSt) monolith. The elution behavior of steroids with different hydrophobicity was evaluated using micro-high-performance liquid chromatography in sole aqueous mobile phase. Temperature dependent interaction changes were observed between steroids and the PNIPAAm modified surfaces. Furthermore, the interaction between bioactive compounds and the PNIPAAm grafted PSt surfaces was controlled and eventually separate these molecules with different hydrophobicities by simple temperature modulation in aqueous environment. The PNIPAAm grafted PSt monolithic capillary showed improved separation properties of bioactive compounds, compared with a PNIPAAm grafted hollow capillary in aqueous environment. PMID:27559999

  17. Dipyridyl-immobilized ionic liquid type hybrid silica monolith for hydrophilic interaction electrochromatography.

    PubMed

    Wang, Xiao; Zheng, Na; Huang, Yifang; Wang, Jiabin; Lin, Xucong; Xie, Zenghong

    2013-11-01

    A pyridinium-based immobilized ionic liquid type multifunctional hybrid silica monolith was prepared by the in situ polymerization of 3-chloropropyl-silica matrix and 4,4'-dipyridyl for hydrophilic interaction CEC. The obtained hybrid monolith possessed of high stable skeletal microstructures with obviously hydrophilic retention mechanism under ACN content >50% in the mobile phase. Strong and stable anodic EOF could be observed under a broad pH range from pH 3.0 to 9.0. Due to the immobilized dipyridyl groups bonded to the silica matrix surface, the resulting hydrophilic hybrid monolith possessed multiple separation interactions including hydrogen bond, π-π, and anion exchange. Excellent separations of various polar analytes including electroneutral phenols, charged acid nucleotides, and basic analytes were successfully achieved. The highest column efficiencies up to 120,000, 164,000, and 106,000 plates/m were obtained for nucleotides, nucleic acid bases, and nucleosides and nicotines, respectively. These results demonstrated that the dipyridyl-immobilized ionic liquid functionalized hybrid monolith possessed highly mechanical stability and good chromatographic performance for hydrophilic interaction electrochromatography.

  18. Preparation of a thermoresponsive polymer grafted polystyrene monolithic capillary for the separation of bioactive compounds.

    PubMed

    Koriyama, Takuya; Asoh, Taka-Aki; Kikuchi, Akihiko

    2016-11-01

    To develop aqueous microseparation columns for bioactive compounds, a thermoresponsive polymer grafted polymer monolith was prepared inside silica capillaries having an I.D. of 100μm by polymerization of styrene (St) with m/p-divinylbenzene (DVB) in the presence of polydimethylsiloxane as porogen, followed by surface-initiated atom transfer radical polymerization (SI-ATRP) of N-isopropylacrylamide (NIPAAm). SEM analysis indicated that the resulting poly(N-isopropylacrylamide) (PNIPAAm) grafted polystyrene monolith had a consecutive three-dimensionally interconnected structure and through-pores, similar to the base polystyrene (PSt) monolith. The elution behavior of steroids with different hydrophobicity was evaluated using micro-high-performance liquid chromatography in sole aqueous mobile phase. Temperature dependent interaction changes were observed between steroids and the PNIPAAm modified surfaces. Furthermore, the interaction between bioactive compounds and the PNIPAAm grafted PSt surfaces was controlled and eventually separate these molecules with different hydrophobicities by simple temperature modulation in aqueous environment. The PNIPAAm grafted PSt monolithic capillary showed improved separation properties of bioactive compounds, compared with a PNIPAAm grafted hollow capillary in aqueous environment.

  19. Preparation of a zeolite-modified polymer monolith for identification of synthetic colorants in lipsticks

    NASA Astrophysics Data System (ADS)

    Wang, Huiqi; Li, Zheng; Niu, Qian; Ma, Jiutong; Jia, Qiong

    2015-10-01

    A novel zeolite-modified poly(methacrylic acid-ethylenedimethacrylate) (zeolite@poly(MAA-EDMA)) monolithic column was prepared with the in situ polymerization method and employed in polymer monolith microextraction for the separation and preconcentration of synthetic colorants combined with high performance liquid chromatography. The polymer was characterized by scanning electronmicroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermo-gravimetric analysis. Various parameters affecting the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, we obtained acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations. The method was applied to the determination of synthetic colorants in lipsticks with recoveries ranged from 70.7% to 109.7%. Compared with conventional methacrylic acid-based monoliths, the developed monolith exhibited high enrichment capacity because of the introduction of zeolites into the preparation process. The extraction efficiency followed the order: zeolite@poly(MAA-EDMA) > poly(MAA-EDMA) > direct HPLC analysis.

  20. A novel polymeric monolith prepared with multi-acrylate crosslinker for retention-independent efficient separation of small molecules in capillary liquid chromatography.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Chen, Lianfang; Zou, Hanfa

    2015-07-01

    Low column efficiency for small molecules in reversed-phase chromatography is a major problem commonly encountered in polymer-based monoliths. Herein, a novel highly crosslinked porous polymeric monolith was in situ prepared by using a multi-acrylate monomer, dipentaerythritol penta-/hexa-acrylate (DPEPA), as crosslinker, which copolymerized with lauryl methacrylate (LMA) as functional monomer in a UV-transparent fused-silica capillary via photo-initiated free-radical polymerization within 5 min. The mechanical stability and permeability of the resulting poly(LMA-co-DPEPA) monolith were characterized in detail. One series of highly crosslinked poly(LMA-co-DPEPA) columns were prepared with relatively higher content of crosslinker (63.3%) in the precursor. Although they exhibited lower permeability, high column efficiency for alkylbenzenes was acquired in cLC, and the minimum plate height (column B) was in the range of 6.04-9.00 μm, corresponding to 111,000-165,000 N m(-1). Meanwhile, another series of poly(LMA-co-DPEPA) columns prepared with relatively lower content of crosslinker (52.7%) in the precursor exhibited higher permeability, but the minimum plate height (column E) was relatively low in the range of 10.75-20.04 μm for alkylbenzenes, corresponding to 50,000-93,000 N m(-1). Compared with common poly(LMA-co-EDMA) columns previously reported, the highly crosslinked poly(LMA-co-DPEPA) columns using a multi-acrylate monomer as crosslinker possessed remarkably high column efficiency for small molecules in cLC. By plotting of plate height (H) of alkylbenzenes versus the linear velocity (u) of mobile phase, the results revealed a retention-independent efficient performance of small molecules in the isocratic elution, indicating that the use of multi-functional crosslinker possibly prevents the generation of gel-like micropores in the poly(LMA-co-DPEPA) monolith, reducing the mass transfer resistance (C-term).

  1. Performance of a Chromolith RP-18e column for the screening of beta-blockers.

    PubMed

    Pous-Torres, Sandra; Ruiz-Angel, Maria-José; Torres-Lapasió, José Ramón; García-Alvarez-Coque, Maria Celia

    2009-08-01

    The chromatographic performance of a monolithic column (Chromolith RP-18e) was comprehensively examined in the isocratic separation of ten beta-blockers, using ACN-water mobile phases, and compared with the performance of three microparticulate RP columns manufactured with different types of silica: Spherisorb ODS-2, Kromasil C18 and XTerra MS C18. The comparison considered the analysis time, selectivity, peak shape (column efficiency and asymmetry) and resolution, and was extended to a wide range of mobile phase compositions. The Chromolith column showed good performance for the analysis of beta-blockers with regard to the packed columns. In terms of selectivity and analysis time, the greatest similarity was found between the Chromolith and XTerra columns. The addition of a silanol blocking agent (0.1% triethylamine) to both Chromolith and Spherisorb columns yielded, apparently, a similar blocking degree of the silanol groups (based on the similar peak shapes), and gave rise to similar selectivity.

  2. Starch columns: Analog model for basalt columns

    NASA Astrophysics Data System (ADS)

    Müller, Gerhard

    1998-07-01

    Desiccation of starch-water mixtures produces tensile-crack patterns which appear to be interesting, but largely unknown study objects for fracture mechanics, structural geology, and volcanology. This paper concentrates on columnar jointing and on columns in starch. Starch columns have polygonal cross sections and are very similar to basalt columns. They are produced by lamp drying starch specimens with dimensions of several centimeters and have diameters in the millimeter range. The columns develop behind a crack front which propagates from the surface into the interior. The experiments, supported by X ray tomograms, show that polygonal regularity of the crack pattern is not present at the surface but develops during penetration. This transition is steered by a minimum-fracture-energy principle. The analogy between basalt cooling and starch desiccation is far reaching: water concentration in starch is analogous to temperature in basalt, both quantities obey diffusion equations, water loss is equivalent to heat loss, the resulting contraction stresses have similar dependences on depth and time, and in both cases the material strength is exceeded. The starch experiments show that column diameters are controlled by the depth gradient of water concentration at the crack front. High (low) gradients are connected with thin (thick) columns. By analogy, a similar relation with the temperature gradient exists for basalt columns. The (normalized) starch gradients are about 3 orders of magnitude larger than the (normalized) gradients in basalt. This explains why starch columns are much thinner than basalt columns. The gradients are so different, because the crack front speeds differ by a factor of about 10: after 3 days the speed is about 10 mm/d in starch but about 100 mm/d in basalt [Peck, 1978]. The speed difference, in turn, results from the difference of the diffusion constants: the hydraulic diffusivity of starch is 2 orders of magnitude lower than the thermal

  3. Sol-gel synthesis of macro-mesoporous titania monoliths and their applications to chromatographic separation media for organophosphate compounds.

    PubMed

    Konishi, Junko; Fujita, Koji; Nakanishi, Kazuki; Hirao, Kazuyuki; Morisato, Kei; Miyazaki, Shota; Ohira, Masayoshi

    2009-10-30

    We have developed a method of independently tailoring the macro- and mesoporous structures in titania (TiO2) monoliths in order to achieve liquid chromatographic separations of phosphorous-containing compounds. Anatase TiO2 monolithic gels with well-defined bicontinuous macropores and microstructured skeletons are obtained via the sol-gel process in strongly acidic conditions using poly(ethylene oxide) as a phase separator and N-methylformamide as a proton scavenger. Aging treatment of the wet gels in the mother liquor at temperatures of 100-200 degrees C and subsequent heat treatment at 400 degrees C allow the formation and control of mesoporous structures with uniform pore size distributions in the gel skeletons, without disturbing the preformed macroporous morphology. The monolithic TiO2 rod columns with bimodal macro-mesoporous structures possess the phospho-sensitivity and exhibit excellent chromatographic separations of phosphorus-containing compounds.

  4. Column Liquid Chromatography.

    ERIC Educational Resources Information Center

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  5. Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides.

    PubMed

    Lamprou, Alexandros; Wang, Hongxia; Saeed, Adeela; Svec, Frantisek; Britt, David; Maya, Fernando

    2015-07-14

    We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process. The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

  6. Grafting zwitterionic polymer onto cryogel surface enhances protein retention in steric exclusion chromatography on cryogel monolith.

    PubMed

    Tao, Shi-Peng; Zheng, Jie; Sun, Yan

    2015-04-10

    Cryogel monoliths with interconnected macropores (10-100μm) and hydrophilic surfaces can be employed as chromatography media for protein retention in steric exclusion chromatography (SXC). SXC is based on the principle that the exclusion of polyethylene glycol (PEG) on both a hydrophilic chromatography surface and a protein favors their association, leading to the protein retention on the chromatography surface. Elution of the retained protein can be achieved by reducing PEG concentration. In this work, the surface of polyacrylamide-based cryogel monolith was modified by grafting zwitterionic poly(carboxybetaine methacrylate) (pCBMA), leading the increase in the surface hydrophilicity. Observation by scanning electron microscopy revealed the presence of the grafted pCBMA chain clusters on the cryogel surface, but pCBMA grafting did not result in the changes of the physical properties of the monolith column, and the columns maintained good recyclability in SXC. The effect of the surface grafting on the SXC behavior of γ-globulin was investigated in a wide flow rate range (0.6-12cm/min). It was found that the dynamic retention capacity increased 1.4-1.8 times by the zwitterionic polymer grafting in the flow rate range of 1.5-12cm/min. The mechanism of enhanced protein retention on the zwitterionic polymer-grafted surface was proposed. The research proved that zwitterionic polymer modification was promising for the development of new materials for SXC applications.

  7. Grafting zwitterionic polymer onto cryogel surface enhances protein retention in steric exclusion chromatography on cryogel monolith.

    PubMed

    Tao, Shi-Peng; Zheng, Jie; Sun, Yan

    2015-04-10

    Cryogel monoliths with interconnected macropores (10-100μm) and hydrophilic surfaces can be employed as chromatography media for protein retention in steric exclusion chromatography (SXC). SXC is based on the principle that the exclusion of polyethylene glycol (PEG) on both a hydrophilic chromatography surface and a protein favors their association, leading to the protein retention on the chromatography surface. Elution of the retained protein can be achieved by reducing PEG concentration. In this work, the surface of polyacrylamide-based cryogel monolith was modified by grafting zwitterionic poly(carboxybetaine methacrylate) (pCBMA), leading the increase in the surface hydrophilicity. Observation by scanning electron microscopy revealed the presence of the grafted pCBMA chain clusters on the cryogel surface, but pCBMA grafting did not result in the changes of the physical properties of the monolith column, and the columns maintained good recyclability in SXC. The effect of the surface grafting on the SXC behavior of γ-globulin was investigated in a wide flow rate range (0.6-12cm/min). It was found that the dynamic retention capacity increased 1.4-1.8 times by the zwitterionic polymer grafting in the flow rate range of 1.5-12cm/min. The mechanism of enhanced protein retention on the zwitterionic polymer-grafted surface was proposed. The research proved that zwitterionic polymer modification was promising for the development of new materials for SXC applications. PMID:25757821

  8. Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides.

    PubMed

    Lamprou, Alexandros; Wang, Hongxia; Saeed, Adeela; Svec, Frantisek; Britt, David; Maya, Fernando

    2015-01-01

    We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process. The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications. PMID:26273850

  9. Separation of selected transition metals by capillary chelation ion chromatography using acetyl-iminodiacetic acid modified capillary polymer monoliths.

    PubMed

    Moyna, Áine; Connolly, Damian; Nesterenko, Ekaterina; Nesterenko, Pavel N; Paull, Brett

    2012-08-01

    Capillary housed laurylmethacrylate-co-ethylene dimethacrylate (LMA-co-EDMA) polymer monoliths were fabricated, functionalised with varying amounts of vinyl azlactone, followed by immobilisation of iminodiacetic acid (IDA), forming a range of acetyl-iminodiacetic acid (AIDA) functionalised monoliths, applied to the chelation ion chromatographic separation of selected transition and heavy metals. A number of monoliths of varying length and ligand density were prepared, resulting in increased cation retention and chromatographic resolution on those displaying the highest capacity. Ligand density and related column capacity were confirmed visually using scanning capacitively coupled contactless conductivity detection (sC(4)D) techniques. Column temperature studies to determine retention mechanism and the effect of temperature on the retention of Mn(II), Cd(II) and Cu(II) was investigated, showing an increase in retention with increased temperature for Cd(II) and Cu(II), whilst a decrease in retention was obtained for Mn(II). Isocratic capillary chelation ion chromatographic separations of Mn(II), Cd(II) and Cu(II) were obtained, with dual peak detection demonstrated using combined on-column C(4)D detection and UV-Visible detection following the post-capillary column reaction of the eluted metals with 4-(2-pyridylazo) resorcinol (PAR).

  10. Fabrication of aluminum terephthalate metal-organic framework incorporated polymer monolith for the microextraction of non-steroidal anti-inflammatory drugs in water and urine samples.

    PubMed

    Lyu, Dan-Ya; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2015-05-01

    Polymer monolith microextraction (PMME) based on capillary monolithic column is an effective and useful technique to preconcentrate trace analytes from environmental and biological samples. Here, we report the fabrication of a novel aluminum terephthalate metal-organic framework (MIL-53(Al)) incorporated capillary monolithic column via in situ polymerization for the PMME of non-steroidal anti-inflammatory drugs (NSAIDs) (ketoprofen, fenbufen and ibuprofen) in water and urine samples. The fabricated MIL-53(Al) incorporated monolith was characterized by X-ray powder diffractometry, scanning electron microscopy, Fourier transform infrared spectrometry, and nitrogen adsorption experiment. The MIL-53(Al) incorporated monolith gave larger surface area than the neat polymer monolith. A 2-cm long MIL-53(Al) incorporated capillary monolith was applied for PMME coupled with high-performance liquid chromatography for the determination of the NSAIDs. Potential factors affecting the PMME were studied in detail. Under the optimized conditions, the developed method gave the enhancement factors of 46-51, the linear range of 0.40-200μgL(-1), the detection limits (S/N=3) of 0.12-0.24μgL(-1), and the quantification limits (S/N=10) of 0.40-0.85μgL(-1). The recoveries for spiked NSAIDs (20μgL(-1)) in water and urine samples were in the range of 77.3-104%. Besides, the MIL-53(Al) incorporated monolith was stable enough for 120 extraction cycles without significant loss of extraction efficiency. The developed method was successfully applied to the determination of NSAIDs in water and urine samples. PMID:25840660

  11. Fabrication of aluminum terephthalate metal-organic framework incorporated polymer monolith for the microextraction of non-steroidal anti-inflammatory drugs in water and urine samples.

    PubMed

    Lyu, Dan-Ya; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2015-05-01

    Polymer monolith microextraction (PMME) based on capillary monolithic column is an effective and useful technique to preconcentrate trace analytes from environmental and biological samples. Here, we report the fabrication of a novel aluminum terephthalate metal-organic framework (MIL-53(Al)) incorporated capillary monolithic column via in situ polymerization for the PMME of non-steroidal anti-inflammatory drugs (NSAIDs) (ketoprofen, fenbufen and ibuprofen) in water and urine samples. The fabricated MIL-53(Al) incorporated monolith was characterized by X-ray powder diffractometry, scanning electron microscopy, Fourier transform infrared spectrometry, and nitrogen adsorption experiment. The MIL-53(Al) incorporated monolith gave larger surface area than the neat polymer monolith. A 2-cm long MIL-53(Al) incorporated capillary monolith was applied for PMME coupled with high-performance liquid chromatography for the determination of the NSAIDs. Potential factors affecting the PMME were studied in detail. Under the optimized conditions, the developed method gave the enhancement factors of 46-51, the linear range of 0.40-200μgL(-1), the detection limits (S/N=3) of 0.12-0.24μgL(-1), and the quantification limits (S/N=10) of 0.40-0.85μgL(-1). The recoveries for spiked NSAIDs (20μgL(-1)) in water and urine samples were in the range of 77.3-104%. Besides, the MIL-53(Al) incorporated monolith was stable enough for 120 extraction cycles without significant loss of extraction efficiency. The developed method was successfully applied to the determination of NSAIDs in water and urine samples.

  12. Phosphonium chloride for thermal storage

    NASA Technical Reports Server (NTRS)

    Sutton, J. G.; Heimlich, P. F.; Tepper, E. H.

    1972-01-01

    Development of systems for storage of thermal energy is discussed. Application of phosphonium chloride for heat storage through reversible dissociation is described. Chemical, physical, and thermodynamic properties of phosphonium chloride are analyzed and dangers in using phosphonium chloride are explained.

  13. Preparation and characterization of an imprinted monolith by atom transfer radical polymerization assisted by crowding agents.

    PubMed

    Ban, Lu; Zhao, Liang; Deng, Bang-Li; Huang, Yan-Ping; Liu, Zhao-Sheng

    2013-03-01

    A method based on reverse atom transfer radical polymerization (R-ATRP) and molecular crowding has been used for design and synthesis of monolithic molecularly imprinted polymers (MIPs) capable of recognizing ibuprofen (IBU). 4-Vinylpyridine (4-VP) was used as the functional monomer, and ethylene glycol dimethacrylate (EDMA) was the crosslinking monomer. Azobisisobutyronitrile (AIBN)-CuCl(2)-N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) was used as the initiating system. Compared with conventional radical polymerization-based IBU-MIPs, the imprinting effects of the obtained IBU-MIPs was enhanced, suggesting the merit of combination of reverse ATRP and molecular crowding. In addition, it was found that the polymerization time of the molecularly imprinted monolithic column, the amount of template, the degree of crosslinking, and the composition of mobile phase greatly affected retention of the template and the performance of molecular recognition.

  14. Variation in the chromatographic, material, and chemical characteristics of methacrylate-based polymer monoliths during photoinitiated low-temperature polymerization.

    PubMed

    Kobayashi, Ayumi; Nakaza, Takuya; Hirano, Tomohiko; Kitagawa, Shinya; Ohtani, Hajime

    2016-07-01

    Both the separation behavior and the structure of a polymer monolith column depends on both the reaction solution composition and the polymerization conditions. In photoinitiated low-temperature polymerization, polymerization temperature, irradiation intensity, and polymerization time were key factors to control the monolith characteristics. In this study, the effect of polymerization time on the chromatographic, material, and chemical characteristics of poly(butyl methacrylate-co-ethylene dimethacrylate) monoliths was studied using pyrolysis-gas chromatography, Raman spectroscopy, inverse size exclusion chromatography, scanning electron microscopy, and chromatographic methods. Both butyl methacrylate and ethylene dimethacrylate monomers were incorporated into the monolith as the polymerization time increased, and it resulted in increases in both the flow resistance (decrease in both permeability and total/through pore porosities) and retention factors. The longer polymerization time led to lower relative amounts of free methacrylate functional groups in the monolith, i.e. cross-linking was enhanced. The increase of the polymerization time from 8 to 12 min significantly reduced the separation efficiency for the retained analyte, whereas an increase in the fraction of the mesoporosity was observed. PMID:27129896

  15. Chloride flux in phagocytes.

    PubMed

    Wang, Guoshun

    2016-09-01

    Phagocytes, such as neutrophils and macrophages, engulf microbes into phagosomes and launch chemical attacks to kill and degrade them. Such a critical innate immune function necessitates ion participation. Chloride, the most abundant anion in the human body, is an indispensable constituent of the myeloperoxidase (MPO)-H2 O2 -halide system that produces the potent microbicide hypochlorous acid (HOCl). It also serves as a balancing ion to set membrane potentials, optimize cytosolic and phagosomal pH, and regulate phagosomal enzymatic activities. Deficient supply of this anion to or defective attainment of this anion by phagocytes is linked to innate immune defects. However, how phagocytes acquire chloride from their residing environment especially when they are deployed to epithelium-lined lumens, and how chloride is intracellularly transported to phagosomes remain largely unknown. This review article will provide an overview of chloride protein carriers, potential mechanisms for phagocytic chloride preservation and acquisition, intracellular chloride supply to phagosomes for oxidant production, and methods to measure chloride levels in phagocytes and their phagosomes. PMID:27558337

  16. Taking a Large Monolith to Use for Teaching Soil Morphology.

    ERIC Educational Resources Information Center

    Smith, B. R.; And Others

    1989-01-01

    Described is a technique for taking a large monolith for the purpose of teaching soil structure. Materials and procedures are detailed. A survey of 93 students indicated that the larger monolith was preferred over the commonly used narrow ones. (CW)

  17. GaAs monolithic RF modules for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Cauley, Michael A.

    1991-01-01

    Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

  18. Open cycle lithium chloride cooling system

    NASA Astrophysics Data System (ADS)

    Lenz, T. G.; Loef, G. O. G.; Iyer, R.; Wenger, J.

    1983-05-01

    A lithium chloride open cycle absorption chiller has been designed, built and tested. Solution reconcentration takes place in a small counter current packed column supplied with solar heated air. Removal of noncondensable gases that enter the chiller dissolved in the strong solution and the make-up refrigerant streams is accomplished by a liquid-jet ejector and a small vacuum pump. Cooling capacities approaching 1.4 tons and COP levels of 0.58 have been achieved at non-optimum operating conditions. Test results from preliminary system operation suggest that mass transfer processes in both the packed column reconcentrator and the absorber are controlled by concentration gradients in the lithium chloride solution. Liquid phase controlled mass transfer dictates an operating strategy different from the previously assumed gas phase controlled process to obtain maximum rates of evaporation in the packed column. Determination of optimal operating conditions leading to decreased electrical power consumption and improved cooling capacity and coefficient of performance will require further analysis and testing.

  19. Designing Catalytic Monoliths For Closed-Cycle CO2 Lasers

    NASA Technical Reports Server (NTRS)

    Guinn, Keith; Herz, Richard K.; Goldblum, Seth; Noskowski, ED

    1992-01-01

    LASCAT (Design of Catalytic Monoliths for Closed-Cycle Carbon Dioxide Lasers) computer program aids in design of catalyst in monolith by simulating effects of design decisions on performance of laser. Provides opportunity for designer to explore tradeoffs among activity and dimensions of catalyst, dimensions of monolith, pressure drop caused by flow of gas through monolith, conversion of oxygen, and other variables. Written in FORTRAN 77.

  20. Consolidation and densification methods for fibrous monolith processing

    SciTech Connect

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2006-06-20

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  1. Inelastic column behavior

    NASA Technical Reports Server (NTRS)

    Duberg, John E; Wilder, Thomas W , III

    1952-01-01

    The significant findings of a theoretical study of column behavior in the plastic stress range are presented. When the behavior of a straight column is regarded as the limiting behavior of an imperfect column as the initial imperfection (lack of straightness) approaches zero, the departure from the straight configuration occurs at the tangent-modulus load. Without such a concept of the behavior of a straight column, one is led to the unrealistic conclusion that lateral deflection of the column can begin at any load between the tangent-modulus value and the Euler load, based on the original elastic modulus. A family of curves showing load against lateral deflection is presented for idealized h-section columns of various lengths and of various materials that have a systematic variation of their stress-strain curves.

  2. Development of a monolithic ferrite memory array

    NASA Technical Reports Server (NTRS)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  3. A 30 GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Mondal, J.; Contolatis, T.; Geddes, J.; Bauhahn, P.; Sokolov, V.

    1990-01-01

    The technical achievements and deliveries made during the duration of the program to develop a 30 GHz monolithic receive module for communication feed array applications and to deliver submodules and 30 GHz monolithic receive modules for experimental evaluation are discussed. Key requirements include an overall receive module noise figure of 5 dB, a 30 dB RF-to-RF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. In addition, the monolithic receive module design addresses a cost goal of less than one thousand dollars (1980 dollars) per module in unit buys of 5,000 or more, and a mechanical configuration that is applicable to a spaceborne phase array system. An additional task for the development and delivery of 32 GHz phase shifter integrated circuit (IC) for deep space communication is also described.

  4. Monolithic and mechanical multijunction space solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1992-01-01

    High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since the two approaches are still in the developmental stage.

  5. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT OF CENTER WITH TOP OF SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  6. Strontium-89 Chloride

    MedlinePlus

    ... ask your doctor or pharmacist for more information.Strontium-89 chloride is in a class of drugs known as radioisotopes. It delivers radiation to cancer sites and ultimately decreases bone pain. The length of treatment depends on the ...

  7. Mercuric chloride poisoning

    MedlinePlus

    ... Mercuric chloride is a very poisonous form of mercury. It is a type of mercury salt. There are different types of mercury poisonings . This article discusses poisoning from swallowing mercuric ...

  8. Hydrogen chloride test set

    NASA Technical Reports Server (NTRS)

    Workman, G. L.

    1976-01-01

    Detector uses tertiary amine, which makes reaction fairly specific for relatively small highly polarized hydrogen chloride molecule. Reaction is monitored by any microbalance capable of measuring extremely small mass differences in real time.

  9. The 30-GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Bauhahn, P.; Geddes, J.; Sokolov, V.; Contolatis, T.

    1988-01-01

    The fourth year progress is described on a program to develop a 27.5 to 30 GHz GaAs monolithic receive module for spaceborne-communication antenna feed array applications, and to deliver submodules for experimental evaluation. Program goals include an overall receive module noise figure of 5 dB, a 30 dB RF to IF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. Submicron gate length single and dual gate FETs are described and applied in the development of monolithic gain control amplifiers and low noise amplifiers. A two-stage monolithic gain control amplifier based on ion implanted dual gate MESFETs was designed and fabricated. The gain control amplifier has a gain of 12 dB at 29 GHz with a gain control range of over 13 dB. A two-stage monolithic low noise amplifier based on ion implanted MESFETs which provides 7 dB gain with 6.2 dB noise figure at 29 GHz was also developed. An interconnected receive module containing LNA, gain control, and phase shifter submodules was built using the LNA and gain control ICs as well as a monolithic phase shifter developed previously under this program. The design, fabrication, and evaluation of this interconnected receiver is presented. Progress in the development of an RF/IF submodule containing a unique ion implanted diode mixer diode and a broadband balanced mixer monolithic IC with on-chip IF amplifier and the initial design of circuits for the RF portion of a two submodule receiver are also discussed.

  10. Polymer network/carbon layer on monolith support and monolith catalytic reactor

    DOEpatents

    Nordquist, Andrew Francis; Wilhelm, Frederick Carl; Waller, Francis Joseph; Machado, Reinaldo Mario

    2003-08-26

    The present invention relates to an improved monolith catalytic reactor and a monolith support. The improvement in the support resides in a polymer network/carbon coating applied to the surface of a porous substrate and a catalytic metal, preferably a transition metal catalyst applied to the surface of the polymer network/carbon coating. The monolith support has from 100 to 800 cells per square inch and a polymer network/carbon coating with surface area of from 0.1 to 15 m.sup.2 /gram as measured by adsorption of N.sub.2 or Kr using the BET method.

  11. Distillation Column Modeling Tools

    SciTech Connect

    2001-09-01

    Advanced Computational and Experimental Techniques will Optimize Distillation Column Operation. Distillation is a low thermal efficiency unit operation that currently consumes 4.8 quadrillion BTUs of energy...

  12. Macroporous silver monoliths using a simple surfactant

    NASA Astrophysics Data System (ADS)

    Khan, Farid; Eswaramoorthy, Muthusamy; Rao, C. N. R.

    2007-01-01

    An elegant method to synthesize porous silver monoliths using a simple surfactant cum reductant, Triton X-114, as the sacrificial template is described. The gel forming property of the surfactant with silver nitrate is utilized to make the porous framework. The monoliths obtained with a mixture of Triton X-114 and dextran have also been examined. A significant improvement in the pore structure was observed when Triton X-114 was used along with Ludox silica sol, followed by calcination and HF treatment. The presence of interparticle pores in the 20-25 nm range on the macroporous silver framework suggests the role of silica spheres in the nanopore formation.

  13. UPDATE ON MONOLITHIC FUEL FABRICATION METHODS

    SciTech Connect

    C. R. Clark; J. F. Jue; G. A. Moore; N. P. Hallinan; B. H. Park; D. E. Burkes

    2006-10-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Progress at INL has led to fabrication of hot isostatic pressed uranium-molybdenum bearing monolithic fuel plates. These miniplates are part of the RERTR-8 miniplate irradiation test. Further progress has also been made on friction stir weld processing which has been used to fabricate full size fuel plates which will be irradiated in the ATR and OSIRIS reactors.

  14. Increased thermal conductivity monolithic zeolite structures

    DOEpatents

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  15. Inflatable Column Structure

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1985-01-01

    Lightweight structural member easy to store. Billowing between circumferential loops of fiber inflated column becomes series of cells. Each fiber subjected to same tension along entire length (though tension is different in different fibers). Member is called "isotensoid" column. Serves as jack for automobiles or structures during repairs. Also used as support for temporary bleachers or swimming pools.

  16. Cyclic performance and simplified pushover analyses of precast segmental concrete bridge columns with circular section

    NASA Astrophysics Data System (ADS)

    Bu, Zhanyu; Guo, Jian; Zheng, Rongyue; Song, Jianwei; Lee, George C.

    2016-06-01

    In recent years, precast segmental concrete bridge columns became prevalent because of the benefits of accelerated construction, low environmental impact, high quality and low life cycle costs. The lack of a detailed configuration and appropriate design procedure to ensure a comparable performance with monolithic construction has impeded this structural system from being widely used in areas of high seismicity. In this study, precast segmental bridge column cyclic loading tests were conducted to investigate the performance of unbonded post-tensioned segmental bridge columns. One monolithic and two precast segmental columns were tested. The precast segmental column exhibited minor damage and small residual displacement after the maximum 7% cyclic drift; energy dissipation (ED) can be enhanced byadding ED bars. The experimental results were modeled by a simplified pushover method (SPOM), as well as a fiber model (FIBM) finite element method. Forty-five cases of columns with different aspect ratios, axial load ratios and ED bar ratios were analyzed with the SPOM and FIBM, respectively. Using these parametric results, a simplified design method was suggested by regressive analysis. Satisfactory correlation was found between the experimental results and the simplified design method for precast segmental columns with different design parameters.

  17. Development of a novel monolith frit-based solid-phase microextraction method for determination of hexanal and heptanal in human serum samples.

    PubMed

    Xu, Hui; Yan, Zhihua; Song, Dandan

    2012-03-01

    In this paper, a polypropylene frit with porous network structure and high area-to-thickness ratio (4.8 mm diameter, 1.6 mm thickness, 20 mm pore size) was utilized as a mould of monolith. Poly(methacrylic acid-ethlyene glycol dimethacrylate) (MAA-EGDMA) monolith was in situ synthesized in the micro-channel of frit by photopolymerization. A monolith frit-based solid-phase microextraction method (SPME) was developed for the determination of hexanal and heptanal in serum samples by combining with high-performance liquid chromatography. 2,4-Dinitrophenylhydrazine (DNPH) as the derivatizing reagent was absorbed on a monolith frit, then its derivatization reaction with aldehydes and the absorption of formed hydrazones on the monolith disk occurred simultaneously. The condition parameters for polymerization, derivatization and extraction were optimized systematically. Under the optimum conditions, rigid structure, low back-pressure and high column capacity were achieved for the monolith frit. The limits of detection for hexanal and heptanal were 1.86 and 1.38 nmol/L, respectively. The inter- and intra-day relative standard deviations were less than 7.7% (n = 6). This method was applied successfully to aldehydes analysis in human serum samples. The method possesses advantages such as simplicity, efficiency, low cost and good biocompatibility. It provides an alternative approach for quantification of aldehydes in complex biological samples.

  18. Glass-silicon column

    DOEpatents

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  19. Constant capacitance in nanopores of carbon monoliths.

    PubMed

    García-Gómez, Alejandra; Moreno-Fernández, Gelines; Lobato, Belén; Centeno, Teresa A

    2015-06-28

    The results obtained for binder-free electrodes made of carbon monoliths with narrow micropore size distributions confirm that the specific capacitance in the electrolyte (C2H5)4NBF4/acetonitrile does not depend significantly on the micropore size and support the foregoing constant result of 0.094 ± 0.011 F m(-2).

  20. Package Holds Five Monolithic Microwave Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Mysoor, Narayan R.; Decker, D. Richard; Olson, Hilding M.

    1996-01-01

    Packages protect and hold monolithic microwave integrated circuit (MMIC) chips while providing dc and radio-frequency (RF) electrical connections for chips undergoing development. Required to be compact, lightweight, and rugged. Designed to minimize undesired resonances, reflections, losses, and impedance mismatches.

  1. Quasi-monolithic tunable optical resonator

    NASA Technical Reports Server (NTRS)

    Arbore, Mark (Inventor); Tapos, Francisc (Inventor)

    2003-01-01

    An optical resonator has a piezoelectric element attached to a quasi-monolithic structure. The quasi-monolithic structure defines an optical path. Mirrors attached to the structure deflect light along the optical path. The piezoelectric element controllably strains the quasi-monolithic structure to change a length of the optical path by about 1 micron. A first feedback loop coupled to the piezoelectric element provides fine control over the cavity length. The resonator may include a thermally actuated spacer attached to the cavity and a mirror attached to the spacer. The thermally actuated spacer adjusts the cavity length by up to about 20 microns. A second feedback loop coupled to the sensor and heater provides a coarse control over the cavity length. An alternative embodiment provides a quasi-monolithic optical parametric oscillator (OPO). This embodiment includes a non-linear optical element within the resonator cavity along the optical path. Such an OPO configuration is broadly tunable and capable of mode-hop free operation for periods of 24 hours or more.

  2. Development of oxide fibrous monolith systems.

    SciTech Connect

    Goretta, K. C.

    1999-03-02

    Fibrous monolithic ceramics generally have a cellular structure that consists of a strong cell surrounded by a weaker boundary phase [1-5]. Fibrous monoliths (FMs) are produced from powders by conventional ceramic fabrication techniques, such as extrusion [1,2]. When properly engineered, they exhibit fail gracefully [3-5]. Several compositions of ceramics and cermets have been processed successfully in fibrous monolithic form [4]. The most thoroughly investigated fibrous monolith consists of Si{sub 3}N{sub 4} cells and a BN cell-boundary phase [3-5]. Through appropriate selection of initial powders and extrusion and hot-pressing parameters, very tough final products have been produced. The resultant high toughness is due primarily to delamination during fracture along textured platelike BN grains. The primary objectives of our program are to develop: (1) Oxide-based FMs, including new systems with improved properties; (2) FMs that can be pressureless sintered rather than hot-pressed; (3) Techniques for continuous extrusion of FM filaments, including solid freeform fabrication (SFF) for net-shape fabrication of FMs; (4) Predictive micromechanical models for FM design and performance; and (5) Ties with industrial producers and users of FMs.

  3. Preparation and evaluation of o-phenanthroline immobilized on a hybrid silica monolith modified with ionic liquids for reversed-phase pressurized capillary electrochromatography.

    PubMed

    Qin, Wenfei; Lü, Haixia; Xie, Zenghong

    2014-12-01

    A novel o-phenanthroline-immobilized ionic-liquid-modified hybrid monolith for capillary electrochromatography was synthesized based on chloropropyl-silica, which was prepared by the in situ polymerization of tetramethoxysilane and 3-chloropropyltrimethoxysilane via a sol-gel process. The morphology of the hybrid monolith was characterized by scanning electron microscopy, and relatively stable anodic electroosmotic flow was observed under a broad pH ranged from pH 3.0 to 9.0. The separation mechanism was investigated by separating four neutral molecules (toluene, dimethylformamide, formamide, and thiourea). The obtained hybrid monolith possessed an obviously reversed-phase retention mechanism, but when the acetonitrile content in the mobile phase was >90% v/v, a weak hydrophilic mechanism was observed on the resultant o-phenanthroline-modified chloropropyl-silica hybrid monolith. The reproducibility of the column was also investigated by measuring relative standard deviations of the migration time for four neutral molecules. Relative standard deviations of run to run (n = 3), day to day (n = 3), and column to column (n = 3) were in the range of 0.4-0.7, 0.9-2.1, and 1.4-3.3%, respectively. Basic separations of various polar analytes including phenols and aromatic amines were successfully achieved.

  4. Monoliths: special issue in a new package.

    PubMed

    Svec, Frantisek

    2013-08-01

    Regular special issues concerning monoliths have always been a stronghold of the Journal of Separation Science. Typically, we issued a call for papers, collected and processed the submitted manuscripts, and all of them were then printed in a single issue of the journal. This approach worked to a certain limit quite acceptably but there was always a longer waiting time between the early submissions and publication. This is why we decided to do it this year differently. I claimed in my 2013 New Years Editorial: "We are living in the electronic era! Why not to make an advantage of that?" And we do. As a result, all manuscript submitted for publication in the special issue Monoliths have already been published in regular issues as soon as they were accepted. The first page of these papers includes a footnote: "This paper is included in the virtual special issue Monoliths available at the Journal of Separation Science website." All papers published with this footnote were collected in a virtual special issue accessible through the internet. This concept ruled out possible delays in publication of contributions submitted early. Since we did not have any real "special issue", there was no need for any hard deadline for submission. We just collected manuscripts submitted for the special issue Monoliths published from January to July 2013 and included them in the virtual special issue. This new approach worked very well and we published 22 excellent papers that are included in the issue available now at this website: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1615-9314/homepage/virtual_special_issue__monoliths.htm. PMID:23939823

  5. Distillation Column Flooding Predictor

    SciTech Connect

    George E. Dzyacky

    2010-11-23

    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  6. Nuclear reactor control column

    DOEpatents

    Bachovchin, Dennis M.

    1982-01-01

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  7. Magnetism-Enhanced Monolith-Based In-Tube Solid Phase Microextraction.

    PubMed

    Mei, Meng; Huang, Xiaojia; Luo, Qing; Yuan, Dongxin

    2016-02-01

    Monolith-based in-tube solid phase microextraction (MB/IT-SPME) has received wide attention because of miniaturization, automation, expected loading capacity, and environmental friendliness. However, the unsatisfactory extraction efficiency becomes the main disadvantage of MB/IT-SPME. To overcome this circumstance, magnetism-enhanced MB/IT-SPME (ME-MB/IT-SPME) was developed in the present work, taking advantage of magnetic microfluidic principles. First, modified Fe3O4 nanoparticles were mixed with polymerization solution and in situ polymerized in the capillary to obtain a magnetic monolith extraction phase. After that, the monolithic capillary column was placed inside a magnetic coil that allowed the exertion of a variable magnetic field. The effects of intensity of magnetic field, adsorption and desorption flow rate, volume of sample, and desorption solvent on the performance of ME-MB/IT-SPME were investigated in detail. The analysis of six steroid hormones in water samples by the combination of ME-MB/IT-SPME with high-performance liquid chromatography with diode array detection was selected as a paradigm for the practical evaluation of ME-MB/IT-SPME. The application of a controlled magnetic field resulted in an obvious increase of extraction efficiencies of the target analytes between 70% and 100%. The present work demonstrated that application of different magnetic forces in adsorption and desorption steps can effectively enhance extraction efficiency of MB/IT-SPME systems. PMID:26742590

  8. Magnetism-Enhanced Monolith-Based In-Tube Solid Phase Microextraction.

    PubMed

    Mei, Meng; Huang, Xiaojia; Luo, Qing; Yuan, Dongxin

    2016-02-01

    Monolith-based in-tube solid phase microextraction (MB/IT-SPME) has received wide attention because of miniaturization, automation, expected loading capacity, and environmental friendliness. However, the unsatisfactory extraction efficiency becomes the main disadvantage of MB/IT-SPME. To overcome this circumstance, magnetism-enhanced MB/IT-SPME (ME-MB/IT-SPME) was developed in the present work, taking advantage of magnetic microfluidic principles. First, modified Fe3O4 nanoparticles were mixed with polymerization solution and in situ polymerized in the capillary to obtain a magnetic monolith extraction phase. After that, the monolithic capillary column was placed inside a magnetic coil that allowed the exertion of a variable magnetic field. The effects of intensity of magnetic field, adsorption and desorption flow rate, volume of sample, and desorption solvent on the performance of ME-MB/IT-SPME were investigated in detail. The analysis of six steroid hormones in water samples by the combination of ME-MB/IT-SPME with high-performance liquid chromatography with diode array detection was selected as a paradigm for the practical evaluation of ME-MB/IT-SPME. The application of a controlled magnetic field resulted in an obvious increase of extraction efficiencies of the target analytes between 70% and 100%. The present work demonstrated that application of different magnetic forces in adsorption and desorption steps can effectively enhance extraction efficiency of MB/IT-SPME systems.

  9. Microminiature gas chromatographic column

    NASA Technical Reports Server (NTRS)

    Donaldson, R. W., Jr.

    1972-01-01

    Techniques commonly used for fabrication of integrated circuits are utilized to produce long capillary tubes for microminiature chromatographs. Method involves bonding of flat silicon plate to top of spirally grooved silicon chip to close groove and form capillary column.

  10. Distillation Column Flooding Predictor

    SciTech Connect

    2002-02-01

    This factsheet describes a research project whose goal is to develop the flooding predictor, an advanced process control strategy, into a universally useable tool that will maximize the separation yield of a distillation column.

  11. Preparation of low flow-resistant methacrylate-based monolithic stationary phases of different hydrophobicity and the application to rapid reversed-phase liquid chromatographic separation of alkylbenzenes at high flow rate and elevated temperature.

    PubMed

    Ueki, Yuji; Umemura, Tomonari; Iwashita, Yoshikazu; Odake, Tamao; Haraguchi, Hiroki; Tsunoda, Kin-ichi

    2006-02-17

    Low flow-resistant alkyl methacrylate-based monolithic stationary phases of different hydrophobicity were constructed for reversed-phase capillary liquid chromatography by thermally initiated radical polymerization of respective methacrylate ester monomer with different alkyl chain (C2, C4, C6, C12, C18) and ethylene glycol dimethacrylate (EDMA) in a 250 microm i.d. fused silica capillary. The hydrophobicity was basically controlled by changing the length and/or the density of the alkyl-chain, while the composition and the ratio of porogenic solvent were adjusted to obtain highly permeable rigid monoliths with adequate column efficiency. Among the prepared monolithic stationary phases, C18-methacrylate monoliths polymerized from a binary porogenic solvent of isoamyl alcohol and 1,4-buthandiol exhibited the most promising performance in terms of hydraulic resistance and column efficiency. The pressure drops of 20-cm long monolithic columns were below approximately 0.4 MPa at a normal linear velocity of 1mm/s (a flow rate of 3 microL/min), and the numbers of theoretical plates for alkylbenzenes mostly exceeded 3000 plates/20 cm. The produced monolithic columns had good mechanical strength for high pressure and temperature, and could be properly operated even at a temperature of 80 degrees C and at a pressure of at least 33 MPa. At 80 degrees C, the theoretical plate numbers reached 6000 plates/20 cm because of the enhanced mass transfer. Due to the novel hydraulic resistance and mechanical strength, the separation time could be reduced 120-fold simply by raising the flow rate and column temperature.

  12. Polyether ether ketone encased monolith frits made of polyether ether ketone tubing with a 0.25 mm opening resulting in an improved separation performance in liquid chromatography.

    PubMed

    Park, Sin Young; Cheong, Won Jo

    2016-05-01

    Tiny polyether ether ketone encased monolith frits have been prepared by modified catalytic sulfonation of the inner surface of polyether ether tubing (1.6 mm od, 0.25 mm id) followed by modified formation of organic monolith and cutting of the tubing into slices. The frit was placed below the central hole of the column outlet union and supported by a combination of a silica capillary (0.365 mm od, 0.05 mm id) and a polyether ether ketone sleeve (1.6 mm od, 0.38 mm id) tightened with a nut and a ferrule when the column was packed to prevent sinking of the frit element into the union hole (0.25 mm opening) otherwise. The column packed this way with the frits investigated in this study has shown better separation performance owing to the reduced frit volume in comparison to the column packed with a commercial stainless-steel screen frit. This study establishes the strategy of disposable microcolumns in which cheap disposable frits are used whenever the column is re-packed to yield columns of even better chromatographic performance than the columns with commercial frits. PMID:26910135

  13. Polyether ether ketone encased monolith frits made of polyether ether ketone tubing with a 0.25 mm opening resulting in an improved separation performance in liquid chromatography.

    PubMed

    Park, Sin Young; Cheong, Won Jo

    2016-05-01

    Tiny polyether ether ketone encased monolith frits have been prepared by modified catalytic sulfonation of the inner surface of polyether ether tubing (1.6 mm od, 0.25 mm id) followed by modified formation of organic monolith and cutting of the tubing into slices. The frit was placed below the central hole of the column outlet union and supported by a combination of a silica capillary (0.365 mm od, 0.05 mm id) and a polyether ether ketone sleeve (1.6 mm od, 0.38 mm id) tightened with a nut and a ferrule when the column was packed to prevent sinking of the frit element into the union hole (0.25 mm opening) otherwise. The column packed this way with the frits investigated in this study has shown better separation performance owing to the reduced frit volume in comparison to the column packed with a commercial stainless-steel screen frit. This study establishes the strategy of disposable microcolumns in which cheap disposable frits are used whenever the column is re-packed to yield columns of even better chromatographic performance than the columns with commercial frits.

  14. Towards Atomic Column-by-Column Spectroscopy

    SciTech Connect

    Pennycook, S.J.; Rafferty, B.

    1998-09-06

    The optical arrangement of the scanning transmission electron microscope (STEM) is ideally suited for performing analysis of individual atomic columns in materials. Using the incoherent Z-contrast image as a reference, and arranging incoherent conditions also for the spectroscopy, a precise correspondence is ensured between features in the inelastic image and elastic signals. In this way the exact probe position needed to maximise the inelastic signal from a selected column can be located and monitored during the analysis using the much higher intensity elastic signal. Although object functions for EELS are typically less than 1 {Angstrom} full width at half maximum, this is still an order of magnitude larger than the corresponding object functions for elastic (or diffuse) scattering used to form the Z-contrast image. Therefore the analysis is performed with an effective probe that is significantly broader than that used for the reference Z-contrast image. For a 2.2 {Angstrom} probe the effective probe is of the order of 2.5 {Angstrom}, while for a 1.3 {Angstrom} probe the effective probe is 1.6 {Angstrom}. Such increases in effective probe size can significantly reduce or even eliminate contrast between atomic columns that are visible in the image. However, this is only true if we consider circular collector apertures. Calculations based upon the theory of Maslen and Rossouw (Maslen and Rossouw 1984; Rossouw and Maslen 1984) show that employing an annular aperture can reduce the FWHM of the inelastic object function down to values close 0.1 {Angstrom}. With practical aperture sizes it should be possible to achieve this increased spatial resolution without loosing too much signal.

  15. Mass transfer kinetics, band broadening and column efficiency.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2012-01-20

    Important progress was recently made in our understanding of the physico-chemical aspects of mass transfer kinetics in chromatographic columns, in methods used for accurate determination of the different contributions to the height equivalent to a theoretical plate (HETP), and in the application of these advances to the elucidation of mass transfer mechanisms in columns packed with recent chromatographic supports (sub-2 μm fully porous particles, sub-3 μm core-shell particles, and monoliths). The independent contributions to the HETP are longitudinal diffusion, eddy dispersion, liquid-solid mass transfer (including trans-particle or trans-skeleton mass transfer and external film mass transfer), and the contributions caused by the thermal heterogeneity of the column. The origin and importance of these contributions are investigated in depth. This work underlines the areas in which improvements are needed, an understanding of the contribution of the external film mass transfer term, a better design of HPLC instruments providing a decrease of the extra-column band broadening contributions to the apparent HETP, the development of better packing procedures giving more radially homogeneous column beds, and new packing materials having a higher thermal conductivity to eliminate the nefarious impact of heat effects in very high pressure liquid chromatography (vHPLC) and supercritical fluid chromatography (SFC).

  16. Effect of minimizing amount of template by addition of macromolecular crowding agent on preparation of molecularly imprinted monolith.

    PubMed

    Sun, Guang-Ying; Zhong, Dan-Dan; Li, Xiang-Jie; Luo, Yu-Qing; Ba, Hang; Liu, Zhao-Sheng; Aisa, Haji Akber

    2015-09-01

    One of the main challenges in the preparation of molecularly imprinted polymers (MIPs) is the substantial initial amount of template needed because of the requirement of high load capacities for most applications. A new strategy of macromolecular crowding was suggested to solve this problem by reducing the amount of template in the polymerization recipe. In a ternary porogenic system of polystyrene (PS) (crowding agent), tetrahydrofuran, and toluene, an imprinted monolithic column with high porosity and good permeability was synthesized using a mixture of ellagic acid (template), acrylamide, and ethylene glycol dimethacrylate. The effect of polymerization factors, including monomer-template molar ratio and the molecular weight and concentration of PS, on the imprinting effect of the resulting MIP monoliths was systematically investigated. At a high ratio of monomer-template (120:1), the greatest imprinting factor of 32.4 was obtained on the MIP monolith with the aid of macromolecular crowding agent. The PS-based imprinted monolith had imprinting even at the extremely high ratio of functional monomer to template of 1510:1. Furthermore, an off-line solid-phase extraction based on the ground MIP was conducted, and the purification recovery of ellagic acid from pomegranate-rind extract was up to 80 %. In conclusion, this approach based on macromolecular crowding is simple, and is especially valuable for those applications of MIP preparation for which a rare template is used.

  17. Biomimetic superelastic graphene-based cellular monoliths.

    PubMed

    Qiu, Ling; Liu, Jeffery Z; Chang, Shery L Y; Wu, Yanzhe; Li, Dan

    2012-01-01

    Many applications proposed for graphene require multiple sheets be assembled into a monolithic structure. The ability to maintain structural integrity upon large deformation is essential to ensure a macroscopic material which functions reliably. However, it has remained a great challenge to achieve high elasticity in three-dimensional graphene networks. Here we report that the marriage of graphene chemistry with ice physics can lead to the formation of ultralight and superelastic graphene-based cellular monoliths. Mimicking the hierarchical structure of natural cork, the resulting materials can sustain their structural integrity under a load of >50,000 times their own weight and can rapidly recover from >80% compression. The unique biomimetic hierarchical structure also provides this new class of elastomers with exceptionally high energy absorption capability and good electrical conductivity. The successful synthesis of such fascinating materials paves the way to explore the application of graphene in a self-supporting, structurally adaptive and 3D macroscopic form. PMID:23212370

  18. Comparison of soil-monolith extraction techniques

    NASA Astrophysics Data System (ADS)

    Meissner, R.; Rupp, H.; Weller, U.; Vogel, H.-J.

    2009-04-01

    In the international literature the term „lysimeter" is used for different objectives, e.g. suction cups, fluxmeters, etc. According to our understanding it belongs to the direct methods to measure water and solute fluxes in soil. Depending on the scientific task the shape and dimensions of the lysimeter as well as the type of filling (disturbed or undisturbed) and the specific instrumentation can be different. In any case where water dynamics or solute transport in natural soil is considered, lysimeters should be filled with 'undisturbed' monoliths which are large enough to contain the small scale heterogeneity of a site since flow and transport is highly sensitive to soil structure. Furthermore, lysimeters with vegetation should represent the natural crop inventory and the maximum root penetration depth should be taken into account. The aim of this contribution is to give an overview about different methods for obtaining undisturbed soil monoliths, in particular about i) techniques for the vertical and ii) for the horizontal extraction and iii) to evaluate the most frequently used procedures based on X-ray tomography images. Minimal disturbance of the soil monolith during extraction and subsequence filling of the lysimeter vessel is of critical importance for establishing flow and transport conditions corresponding approximately to natural field conditions. In the past, several methods were used to extract and fill lysimeter vessels vertically - including hand digging, employing sets of trihedral scaffold with lifting blocks and ballast, or using heavy duty excavators, which could shear and cut large blocks of soil. More recently, technologies have been developed to extract cylindrical soil monoliths by using ramming equipment or screw presses. One of the great disadvantages of the mentioned methods is the compaction or settling of soil that occurs during the "hammering" or "pressing". For this reason a new technology was developed, which cuts the outline of

  19. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Allen, Phillip Grant (Inventor)

    2015-01-01

    A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

  20. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Allen, Phillip Grant (Inventor)

    2016-01-01

    A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

  1. Monolithic Optical-To-Electronic Receiver

    NASA Technical Reports Server (NTRS)

    Kunath, Richard; Mactaggert, Ross

    1994-01-01

    Monolithic optoelectronic integrated circuit converts multiplexed digital optical signals into electrical signals, separates, and distributes them to intended destinations. Developed to deliver phase and amplitude commands to monolithic microwave integrated circuits (MMIC's) at elements of millimeter-wave phased-array antenna from single optical fiber driven by external array controller. Also used in distribution of high-data-rate optical communications in local-area networks (LAN's). Notable features include options for optical or electrical clock inputs; outputs for raw data, addresses, and instructions for diagnosis; and optical-signal-detection circuit used to reduce power consumption by 80 percent between data-transmission times. Chip fabricated by processes available at many major semiconductor foundries. Distribution of digital signals in aircraft, automobiles, and ships potential application.

  2. Monolithic solid oxide fuel cell development

    NASA Technical Reports Server (NTRS)

    Myles, K. M.; Mcpheeters, C. C.

    1989-01-01

    The feasibility of the monolithic solid oxide fuel cell (MSOFC) concept has been proven, and the performance has been dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials have been minimized, thus allowing successful fabrication of the MSOFC with few defects. The MSOFC shows excellent promise for development into a practical power source for many applications from stationary power, to automobile propulsion, to space pulsed power.

  3. Monolithic microextraction tips by emulsion photopolymerization.

    PubMed

    Liang, Shih-Shin; Chen, Shu-Hui

    2009-03-20

    Monoliths formed by photopolymerization are excellent means for fabricating functional elements in miniaturized microdevices such as microextraction tips which are becoming important for sample preparation. Various silica-based and polymer-based materials have been used to fabricate monoliths with through pores of several nm to 4 microm. However, the back pressure created by such methods is still considered to be high for microtips that use suction forces to deliver the liquid. In this study, we demonstrated that emulsion techniques such as oil-in-water can be used to form monoliths with large through pores (>20 microm), and with rigid structures on small (10 microL) and large (200 microL) pipette tips by photopolymerization. We further showed that, with minor modifications, various functionalized particles (5-20 microm) can be added to form stable emulsions and successfully encapsulated into the monoliths for qualitative and quantitative solid-phase microextractions for a diverse application. Due to high permeability and large surface area, quick equilibration can be achieved by pipetting to yield high recovery rates. Using tryptic digests of ovalbumin as the standard, we obtained a recovery yield of 90-109% (RSD: 10-16%) with a loading capacity of 3 mug for desalting tips immobilized with C18 beads. Using tryptic digests of beta-casein and alpha-casein as standards, we showed that phosphopeptides were substantially enriched by tips immobilized with immobilized metal affinity chromatography or TiO(2) materials. Using estrogenic compounds as standards, we obtained a recovery yield of 95-108% (RSD: 10-12%) and linear calibration curves ranging from 5 to 100 ng (R(2)>0.99) for Waters Oasis HLB tips immobilized with hydrophilic beads. PMID:19203757

  4. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    SciTech Connect

    Jantzen, C

    2006-12-22

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydroceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form.

  5. Fluidized Bed Steam Reformer (FBSR) monolith formation

    SciTech Connect

    Jantzen, C.M.

    2007-07-01

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or 'mineralized' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydro-ceramics. All but one of the nine monoliths tested met the <2 g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydro-ceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form. (authors)

  6. Update On Monolithic Fuel Fabrication Development

    SciTech Connect

    C. R Clark; J. M. Wight; G. C. Knighton; G. A. Moore; J. F. Jue

    2005-11-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Advancements have been made in the production of U-Mo foil including full sized foils. Progress has also been made in the friction stir welding and transient liquid phase bonding fabrication processes resulting in better bonding, more stable processes and the ability to fabricate larger fuel plates.

  7. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, M.W.; Coronado, P.R.; Hair, L.M.

    1995-03-07

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels. 6 figs.

  8. Monolithic 3D CMOS Using Layered Semiconductors.

    PubMed

    Sachid, Angada B; Tosun, Mahmut; Desai, Sujay B; Hsu, Ching-Yi; Lien, Der-Hsien; Madhvapathy, Surabhi R; Chen, Yu-Ze; Hettick, Mark; Kang, Jeong Seuk; Zeng, Yuping; He, Jr-Hau; Chang, Edward Yi; Chueh, Yu-Lun; Javey, Ali; Hu, Chenming

    2016-04-01

    Monolithic 3D integrated circuits using transition metal dichalcogenide materials and low-temperature processing are reported. A variety of digital and analog circuits are implemented on two sequentially integrated layers of devices. Inverter circuit operation at an ultralow supply voltage of 150 mV is achieved, paving the way to high-density, ultralow-voltage, and ultralow-power applications. PMID:26833783

  9. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, Michael W.; Coronado, Paul R.; Hair, Lucy M.

    1995-01-01

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels.

  10. Nanoporous Carbon Monoliths with Tunable Thermal Insulation and Mechanical Properties.

    PubMed

    Wang, Xiaopeng; Chen, Fenghua; Luo, Zhenhua; Li, Hao; Zhao, Tong

    2016-01-01

    In this work, nanoscale porous carbon monoliths, with excellent compressive strength and thermal insulation, were obtained with a simple method of carbonizing cured phenol-formaldehyde resin/poly(methyl methacrylate) blends. Apparent density, pore size and morphology of the carbon monoliths were tailored by changing the composition, curing process and carbonization temperature. The continuous nanopores played a key role in enhancing mechanical and thermal performance of the carbon materials. When PMMA concentration was 25%, apparent density and thermal conductivity of the nanoporous carbonaceous monoliths were obtained as low as 1.07 g · cm⁻³ and 0.42 W/(m · K), decreasing by 29.4% and 35.4% than that of carbonaceous monoliths obtained from pure PF; while compressive strength of the nanoporous carbonaceous monoliths was as high as 34 MPa, which was improved over five times than that of pure PF carbon monoliths. PMID:27398592

  11. Nanoporous Carbon Monoliths with Tunable Thermal Insulation and Mechanical Properties.

    PubMed

    Wang, Xiaopeng; Chen, Fenghua; Luo, Zhenhua; Li, Hao; Zhao, Tong

    2016-01-01

    In this work, nanoscale porous carbon monoliths, with excellent compressive strength and thermal insulation, were obtained with a simple method of carbonizing cured phenol-formaldehyde resin/poly(methyl methacrylate) blends. Apparent density, pore size and morphology of the carbon monoliths were tailored by changing the composition, curing process and carbonization temperature. The continuous nanopores played a key role in enhancing mechanical and thermal performance of the carbon materials. When PMMA concentration was 25%, apparent density and thermal conductivity of the nanoporous carbonaceous monoliths were obtained as low as 1.07 g · cm⁻³ and 0.42 W/(m · K), decreasing by 29.4% and 35.4% than that of carbonaceous monoliths obtained from pure PF; while compressive strength of the nanoporous carbonaceous monoliths was as high as 34 MPa, which was improved over five times than that of pure PF carbon monoliths.

  12. Chloride Channels of Intracellular Membranes

    PubMed Central

    Edwards, John C.; Kahl, Christina R.

    2010-01-01

    Proteins implicated as intracellular chloride channels include the intracellular ClC proteins, the bestrophins, the cystic fibrosis transmembrane conductance regulator, the CLICs, and the recently described Golgi pH regulator. This paper examines current hypotheses regarding roles of intracellular chloride channels and reviews the evidence supporting a role in intracellular chloride transport for each of these proteins. PMID:20100480

  13. Eruption column physics

    SciTech Connect

    Valentine, G.A.

    1997-03-01

    In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

  14. Less common applications of monoliths III. Gas chromatography

    PubMed Central

    Svec, Frantisek; Kurganov, Alexander A.

    2008-01-01

    Porous polymer monoliths emerged about two decades ago. Despite this short time, they are finding applications in a variety of fields. In addition to the most common and certainly best known use of this new category of porous media as stationary phases in liquid chromatography, monolithic materials also found their applications in other areas. This review article focuses on monoliths in capillaries designed for separations in gas chromatography. PMID:17645884

  15. Solid-phase microextraction of phthalate esters in water sample using different activated carbon-polymer monoliths as adsorbents.

    PubMed

    Lirio, Stephen; Fu, Chung-Wei; Lin, Jhih-Yun; Hsu, Meng-Ju; Huang, Hsi-Ya

    2016-07-13

    In this study, the application of different activated carbon-polymer (AC-polymer) monoliths as adsorbents for the solid-phase microextraction (SPME) of phthalate esters (PAEs) in water sample were investigated. The activated carbon (AC) was embedded in organic polymers, poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-EDMA)) or poly(styrene-co-divinylbenzene) (poly(STY-DVB)), via a 5-min microwave-assisted or a 15-min water bath heating polymerization. Preliminary investigation on the performance of the native poly(BMA-EDMA) and poly(STY-DVB) demonstrated remarkable adsorption efficiencies for PAEs. However, due to the strong hydrophobic, π-π, and hydrogen bonding interactions between the analytes and polymers, low extraction recoveries were achieved. In contrast, the presence of AC in native polymers not only enhanced the adsorption efficiencies but also assisted the PAE desorption, especially for AC-poly(STY-DVB) with extraction recovery ranged of 76.2-99.3%. Under the optimized conditions, the extraction recoveries for intra-, inter-day and column-to-column were in the range of 76.5-100.8% (<3.7% RSDs), 77.2-97.6% (<5.6% RSDs) and 75.5-99.7% (<6.2% RSDs), respectively. The developed AC-poly(STY-DVB) monolithic column showed good mechanical stability, which can be reused for more than 30 extraction times without any significant loss in the extraction recoveries of PAEs. The AC-poly(STY-DVB) monolithic column was successfully applied in SPME of PAEs in water sample with extraction recovery ranged of 78.8%-104.6% (<5.5% RSDs). PMID:27237837

  16. Monolithic fuel cell based power source for sprint power generation

    NASA Astrophysics Data System (ADS)

    Fee, D. C.; Busch, D. E.; Dees, D. W.; Dusek, J.; Easler, T. E.; Ellingson, W. A.; Flandermeyer, B. K.; Fousek, R. J.; Heiberger, J. J.; Majumdar, S.

    A unique fuel cell (monolith) coupled with a low power nuclear reactor presents an attractive approach for SDI burst power requirements. The high power, long duration bursts, appear achievable within a single shuttle launch limitation with appropriate development of the concept. The feasibility of the monolithic fuel cell concept has been demonstrated. Small arrays (stacks) of the monolithic design have been operated for hundreds of hours. The challenge is to improve the fabrication technology so that larger array of the monolithic design can be operated.

  17. Consolidation and densification methods for fibrous monolith processing

    DOEpatents

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2004-05-25

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered in an inert gas or nitrogen gas at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  18. Chloride channels as drug targets

    PubMed Central

    Verkman, Alan S.; Galietta, Luis J. V.

    2013-01-01

    Chloride channels represent a relatively under-explored target class for drug discovery as elucidation of their identity and physiological roles has lagged behind that of many other drug targets. Chloride channels are involved in a wide range of biological functions, including epithelial fluid secretion, cell-volume regulation, neuroexcitation, smooth-muscle contraction and acidification of intracellular organelles. Mutations in several chloride channels cause human diseases, including cystic fibrosis, macular degeneration, myotonia, kidney stones, renal salt wasting and hyperekplexia. Chloride-channel modulators have potential applications in the treatment of some of these disorders, as well as in secretory diarrhoeas, polycystic kidney disease, osteoporosis and hypertension. Modulators of GABAA (γ-aminobutyric acid A) receptor chloride channels are in clinical use and several small-molecule chloride-channel modulators are in preclinical development and clinical trials. Here, we discuss the broad opportunities that remain in chloride-channel-based drug discovery. PMID:19153558

  19. Boronate affinity monolith with a gold nanoparticle-modified hydrophilic polymer as a matrix for the highly specific capture of glycoproteins.

    PubMed

    Wu, Ci; Liang, Yu; Zhao, Qun; Qu, Yanyan; Zhang, Shen; Wu, Qi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2014-07-01

    As low abundance is the great obstacle for glycoprotein analysis, the development of materials with high efficiency and selectivity for glycoprotein enrichment is a prerequisite in glycoproteome research. Herein, we report a new kind of hydrophilic boronate affinity monolith by attaching 4-mercaptophenylboronic acid (MPBA) with 2-mercaptoethylamine (MPA) on the gold nanoparticle-modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate)) monolith for glycoprotein enrichment. With poly(ethylene glycol) diacrylate as the cross-linker and the further modification of gold nanoparticles, the matrix has advantages of good hydrophilicity and enhanced surface area, which are beneficial to improve the enrichment selectivity and efficiency for glycoproteins. The attachment of MPBA and MPA provide intramolecular BN coordination, which could further enhance the specificity of glycoprotein capture. Such a boronate affinity monolith was applied to enrich horseradish peroxidase (HRP) from the mixture of HRP and bovine serum albumin (BSA), and high selectivity was obtained even at a mass ratio of 1:1000. In addition, the binding capacity of ovalbumin on such monolith reached 390 μg g(-1) . Furthermore, the average recovery of HRP on the prepared affinity monoliths was (84.8±1.9) %, obtained in three times enrichment with the same column. Finally, the boronate affinity monolith was successfully applied for the human-plasma glycoproteome analysis. As a result, 160 glycoproteins were credibly identified from 9 μg of human plasma, demonstrating the great potential of such a monolith for large-scale glycoproteome research.

  20. Solute transport through large uniform and layered soil columns

    NASA Astrophysics Data System (ADS)

    Porro, I.; Wierenga, P. J.; Hills, R. G.

    1993-04-01

    Solute transport experiments are often conducted with homogeneous soils, whereas transport in real situations takes place in heterogeneous soils. An experiment was conducted to compare unsaturated solute transport through uniform and layered soils. Pulse inputs of tritiated water, bromide and chloride were applied under steady flow conditions to the tops of two large (0.95 m diameter by 6 m deep) soil columns. One column was uniformly filled with loamy fine sand and the other filled with alternating 20-cm-thick layers of loamy fine sand and silty clay loam. Soil solution samples were collected during the experiment with suction candles installed at various depths in the columns. Solute transport parameters were estimated by fitting the convection-dispersion equation to the observed breakthrough curves for each solute at various depths in each column. The match between the resulting calibrated curves and the experiment was better for the layered soil column than for the uniform soil column. The results displayed no clear relationship between the dispersion coefficients and depth for any of the tracers for either column. However, dispersivities were greater in the uniform column (3.5 cm) than in the layered column (1.2 cm), while retardation factors for bromide and chloride were similar (0.8 and 0.83, respectively, for the uniform and layered columns). A retardation factor less than one is attributed to anion exclusion. There was evidence of preferential flow in the uniform soil column. The peak concentrations at 5 m depth were greater than those observed at 4 m. Such behavior is inconsistent with one-dimensional flow. Similar results were observed in an experiment performed 3.5 years earlier using the same soil column and approximately the same flow rates, but using a different tracer and associated chemical analysis, different soil saturation prior to the execution of the experiment, and different experimental personnel. This supports the thesis that the anomalous

  1. C₁₈-bound porous silica monolith particles as a low-cost high-performance liquid chromatography stationary phase with an excellent chromatographic performance.

    PubMed

    Ali, Faiz; Cheong, Won Jo

    2014-12-01

    Ground porous silica monolith particles with an average particle size of 2.34 μm and large pores (363 Å) exhibiting excellent chromatographic performance have been synthesized on a relatively large scale by a sophisticated sol-gel procedure. The particle size distribution was rather broad, and the d(0.1)/d(0.9) ratio was 0.14. The resultant silica monolith particles were chemically modified with chlorodimethyloctadecylsilane and end-capped with a mixture of hexamethyldisilazane and chlorotrimethylsilane. Very good separation efficiency (185,000/m) and chromatographic resolution were achieved when the C18 -bound phase was evaluated for a test mixture of five benzene derivatives after packing in a stainless-steel column (1.0 mm × 150 mm). The optimized elution conditions were found to be 70:30 v/v acetonitrile/water with 0.1% trifluoroacetic acid at a flow rate of 25 μL/min. The column was also evaluated for fast analysis at a flow rate of 100 μL/min, and all the five analytes were eluted within 3.5 min with reasonable efficiency (ca. 60,000/m) and resolution. The strategy of using particles with reduced particle size and large pores (363 Å) combined with C18 modification in addition to partial-monolithic architecture has resulted in a useful stationary phase (C18 -bound silica monolith particles) of low production cost showing excellent chromatographic performance.

  2. Poly(glycidyl methacrylate-co-N-methylolacrylamide-co-ethylene dimethacrylate) monolith coupled to high-performance liquid chromatography for the determination of adenosine phosphates in royal jelly.

    PubMed

    Liu, Dan; Zhang, Tianbin; Cheng, Yechun; Jia, Qiong

    2014-07-01

    A polymer monolith microextraction method coupled with high-performance liquid chromatography was developed for the determination of adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. The monolithic column was synthesized inside fused-silica capillaries using thermal initiation free-radical polymerization with glycidyl methacrylate as the monomer, ethylene dimethacrylate as the cross-linker, cyclohexanol, and 1-dodecanol as the porogen. N-Methylolacrylamide, an important hydrophilic monomer, was incorporated into the polymerization mixture to enhance the hydrophilicity of the poly(glycidyl methacrylate-co-ethylene dimethacrylate) column. The obtained poly(glycidyl methacrylate-co-N-methylolacrylamide-co-ethylene dimethacrylate) monolith was characterized by scanning electron microscopy, Fourier-transform infrared spectra, and X-ray photoelectron spectroscopy. Optimum conditions for the preconcentration and separation of the target adenosines were also investigated. Under the optimum conditions, we obtained acceptable linearities, low limits of detection, and good relative standard deviations. The developed polymer monolith microextraction with high-performance liquid chromatography method exhibited a good performance with recovery values in the range of 76.9-104.7% when applied to the determination of the adenosines in five royal jelly samples.

  3. Chromatographic efficiency comparison of polyhedral oligomeric silsesquioxanes-containing hybrid monoliths via photo- and thermally-initiated free-radical polymerization in capillary liquid chromatography for small molecules.

    PubMed

    Wang, Hongwei; Ou, Junjie; Liu, Zhongshan; Lin, Hui; Peng, Xiaojun; Zou, Hanfa

    2015-09-01

    Monolithic poly(methacrylate epoxy cyclosiloxane-co-polyhedral oligomeric silsesquioxanes) (epoxy-MA-POSS) capillary columns have been prepared via either photo- or thermally-initiated polymerization of the corresponding monomers using a 1-propanol/PEG 400 mixture as porogens. Photochemical polymerization was accomplished by irradiation of the UV-transparent capillary for 10min at room temperature, while thermal polymerization was performed at 55°C, 60°C or 65°C for 18h. The evaluation of chromatographic property for two hybrid epoxy-MA-POSS monoliths was carried out. The results indicate that hybrid monoliths fabricated by photochemical initiation exhibit higher column efficiency (97,000-98,400plates/m) than those synthesized by thermal polymerization (41,100-48,000plates/m) in cLC. The higher efficiency of photo-initiated hybrid monoliths is closely related to lower eddy dispersion (A-term) and mass transfer resistance (C-term).

  4. Columns in Clay

    ERIC Educational Resources Information Center

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  5. A Column Dispersion Experiment.

    ERIC Educational Resources Information Center

    Corapcioglu, M. Y.; Koroglu, F.

    1982-01-01

    Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

  6. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    NASA Astrophysics Data System (ADS)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  7. Effect of solvents on physical properties and release characteristics of monolithic hydroxypropylmethylcellulose matrix granules and tablets.

    PubMed

    Cao, Qing-Ri; Choi, Yun-Woong; Cui, Jing-Hao; Lee, Beom-Jin

    2005-04-01

    Effect of solvents on physical characteristics and release characteristics of monolithic acetaminophen (APAP) hydroxypropylmethylcellulose (HPMC) matrix granules and tablets were examined. Various types and amounts of solvents were employed for granulation and cOAting. APAP and other excipients were mixed and were then wet-granulated in a high-speed mixer. The dried granules were then directly compressed and film-coated with low viscosity grade HPMC. As the amount of water increased, the size of granules also increased, showing more spherical and regular shape. However, manufacturing problems such as capping and lamination in tableting occurred when water was used alone as a granulating solvent. The physical properties of HPMC matrix granules were not affected by the batch size. The initial release rate as well as the amount of APAP dissolved had a tendency to decrease as the water level increased. Addition of nonaqueous solvent like ethanol to water resulted in good physical properties of granules. When compared to water/ethanol as a coating solvent, the release rate of film-coated HPMC matrix tablets was more sensitive to the conditions of coating and drying in methylene chloride/ethanol. Most of all, monolithic HPMC matrix tablet when granulated in ethanol/water showed dual release with about 50% drug release immediately within few minutes followed by extended release. It was evident that the type and amount of solvents (mainly water and ethanol) were very important for wet granulation and film-coating of monolithic HPMC matrix tablet, because the plastic deforming and fragmenting properties of material were changed by the different strengths of the different solvents. PMID:15918526

  8. Monolithic aerogels with nanoporous crystalline phases

    NASA Astrophysics Data System (ADS)

    Daniel, Christophe; Guerra, Gaetano

    2015-05-01

    High porosity monolithic aerogels with nanoporous crystalline phases can be obtained from syndiotactic polystyrene and poly(2,6-dimethyl-1,4-phenylene)oxide thermoreversible gels by removing the solvent with supercritical CO2. The presence of crystalline nanopores in the aerogels based on these polymers allows a high uptake associated with a high selectivity of volatile organic compounds from vapor phase or aqueous solutions even at very low activities. The sorption and the fast kinetics make these materials particularly suitable as sorption medium to remove traces of pollutants from water and moist air.

  9. Monolithic LTCC seal frame and lid

    DOEpatents

    Krueger, Daniel S.; Peterson, Kenneth A.; Stockdale, Dave; Duncan, James Brent; Riggs, Bristen

    2016-06-21

    A method for forming a monolithic seal frame and lid for use with a substrate and electronic circuitry comprises the steps of forming a mandrel from a ceramic and glass based material, forming a seal frame and lid block from a ceramic and glass based material, creating a seal frame and lid by forming a compartment and a plurality of sidewalls in the seal frame and lid block, placing the seal frame and lid on the mandrel such that the mandrel fits within the compartment, and cofiring the seal frame and lid block.

  10. Method of fabricating a monolithic solid oxide fuel cell

    DOEpatents

    Minh, N.Q.; Horne, C.R.

    1994-03-01

    In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array. 10 figures.

  11. Method of fabricating a monolithic solid oxide fuel cell

    DOEpatents

    Minh, Nguyen Q.; Horne, Craig R.

    1994-01-01

    In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array.

  12. Fibrous monoliths: Economic ceramic matrix composites from powders [Final report

    SciTech Connect

    Rigali, Mark; Sutaria, Manish; Mulligan, Anthony; Creegan, Peter; Cipriani, Ron

    1999-05-26

    The project was to develop and perform pilot-scale production of fibrous monolith composites. The principal focus of the program was to develop damage-tolerant, wear-resistant tooling for petroleum drilling applications and generate a basic mechanical properties database on fibrous monolith composites.

  13. [Applications of polymeric monoliths in separation of bio-macromolecules].

    PubMed

    Bai, Ligai; Niu, Wenjing; Yang, Gengliang

    2013-04-01

    In recent years, the applications of high performance liquid chromatographic polymeric monoliths in the separation of macromolecules have been developed. In the review, the characters and new developments of bio-macromolecules separation by using the polymeric monoliths, combining with the works in our laboratory are summarized. Moreover, related influential reports are referred.

  14. Creating deep soil core monoliths: Beyond the solum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil monoliths serve as useful teaching aids in the study of the Earth’s critical zone where rock, soil, water, air, and organisms interact. Typical monolith preparation has so far been confined to the 1 to 2-m depth of the solum. Critical ecosystem services provided by soils include materials from ...

  15. Catalytic Ignition and Upstream Reaction Propagation in Monolith Reactors

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

    2007-01-01

    Using numerical simulations, this work demonstrates a concept called back-end ignition for lighting-off and pre-heating a catalytic monolith in a power generation system. In this concept, a downstream heat source (e.g. a flame) or resistive heating in the downstream portion of the monolith initiates a localized catalytic reaction which subsequently propagates upstream and heats the entire monolith. The simulations used a transient numerical model of a single catalytic channel which characterizes the behavior of the entire monolith. The model treats both the gas and solid phases and includes detailed homogeneous and heterogeneous reactions. An important parameter in the model for back-end ignition is upstream heat conduction along the solid. The simulations used both dry and wet CO chemistry as a model fuel for the proof-of-concept calculations; the presence of water vapor can trigger homogenous reactions, provided that gas-phase temperatures are adequately high and there is sufficient fuel remaining after surface reactions. With sufficiently high inlet equivalence ratio, back-end ignition occurs using the thermophysical properties of both a ceramic and metal monolith (coated with platinum in both cases), with the heat-up times significantly faster for the metal monolith. For lower equivalence ratios, back-end ignition occurs without upstream propagation. Once light-off and propagation occur, the inlet equivalence ratio could be reduced significantly while still maintaining an ignited monolith as demonstrated by calculations using complete monolith heating.

  16. Monolithic porous graphitic carbons obtained through catalytic graphitization of carbon xerogels

    NASA Astrophysics Data System (ADS)

    Kiciński, Wojciech; Norek, Małgorzata; Bystrzejewski, Michał

    2013-01-01

    Pyrolysis of organic xerogels accompanied by catalytic graphitization and followed by selective-combustion purification was used to produce porous graphitic carbons. Organic gels impregnated with iron(III) chloride or nickel(II) acetate were obtained through polymerization of resorcinol and furfural. During the pyrolysis stage graphitization of the gel matrix occurs, which in turn develops mesoporosity of the obtained carbons. The evolution of the carbon into graphitic structures is strongly dependent on the concentrations of the transition metal. Pyrolysis leads to monoliths of carbon xerogel characterized by substantially enhanced mesoporosity resulting in specific surface areas up to 400 m2/g. Removal of the amorphous carbon by selective-combustion purification reduces the xerogels' mesoporosity, occasionally causing loss of their mechanical strength. The graphitized carbon xerogels were investigated by means of SEM, XRD, Raman scattering, TG-DTA and N2 physisorption. Through this procedure well graphitized carbonaceous materials can be obtained as bulk pieces.

  17. Purification of influenza deoxyribonucleic acid-based vaccine using agmatine monolith.

    PubMed

    Bicho, D; Caramelo-Nunes, C; Sousa, A; Sousa, F; Queiroz, J A; Tomaz, C T

    2016-02-15

    Lately, researchers have made several efforts to improve vaccine production to fight highly contagious respiratory diseases like influenza. One of the most promising options for reducing the impact of this virus is DNA vaccination. However, a large quantity of highly pure plasmid DNA (pDNA) is necessary to attain this goal. The present work describes the production and purification of the plasmid NTC7482-41H-VA2HA expressing influenza virus hemagglutinin using an agmatine monolith. This ligand was chosen to purify supercoiled (sc) pDNA from complex lysates because of its versatile multimodal character. Its natural intervention in several biological systems together with its similarity with the highly studied arginine ligand allowed the development of a simpler and more specific purification process. Agmatine works under two strategies: descending ammonium sulfate gradient and ascending sodium chloride gradient. Furthermore, pH manipulation revealed an important role in pDNA isoforms selectivity. Dynamic binding capacity (DBC) experiments were performed varying different parameters and showed an increase with pDNA concentration, while high flow rate and high pH had the opposite effect. Sc pDNA was purified with high yield and was efficient with respect to cell transfection and cell viability. This monolith showed to be appropriate to purify the plasmid NTC7482-41H-VA2HA, providing a valuable tool for pDNA influenza vaccines preparation. PMID:26827278

  18. Purification of influenza deoxyribonucleic acid-based vaccine using agmatine monolith.

    PubMed

    Bicho, D; Caramelo-Nunes, C; Sousa, A; Sousa, F; Queiroz, J A; Tomaz, C T

    2016-02-15

    Lately, researchers have made several efforts to improve vaccine production to fight highly contagious respiratory diseases like influenza. One of the most promising options for reducing the impact of this virus is DNA vaccination. However, a large quantity of highly pure plasmid DNA (pDNA) is necessary to attain this goal. The present work describes the production and purification of the plasmid NTC7482-41H-VA2HA expressing influenza virus hemagglutinin using an agmatine monolith. This ligand was chosen to purify supercoiled (sc) pDNA from complex lysates because of its versatile multimodal character. Its natural intervention in several biological systems together with its similarity with the highly studied arginine ligand allowed the development of a simpler and more specific purification process. Agmatine works under two strategies: descending ammonium sulfate gradient and ascending sodium chloride gradient. Furthermore, pH manipulation revealed an important role in pDNA isoforms selectivity. Dynamic binding capacity (DBC) experiments were performed varying different parameters and showed an increase with pDNA concentration, while high flow rate and high pH had the opposite effect. Sc pDNA was purified with high yield and was efficient with respect to cell transfection and cell viability. This monolith showed to be appropriate to purify the plasmid NTC7482-41H-VA2HA, providing a valuable tool for pDNA influenza vaccines preparation.

  19. 11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH FLOOR WAREHOUSE SPACE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Becker-Hazelton Company Warehouse, 280 Iowa Street, Dubuque, Dubuque County, IA

  20. Successfully downsize trayed columns

    SciTech Connect

    Sloley, A.W.; Fleming, B. )

    1994-03-01

    Techniques for the design and sizing of new trayed distillation columns are abundant in the literature. So, too, are the guidelines for modifying towers for operation beyond their original design range. Reducing capacity of distillation trays merits at least as much consideration. Indeed, lack of knowledge and experience in this area causes many tower failures and misdesigned columns. In this article, the authors present some practical design considerations, based on field experience, for tower trays operating at loadings dramatically lower than normal for a particular design. General considerations cover liquid and vapor hydraulics and flow behavior. Case studies are included for there typical units: a refinery vacuum crude still, a petrochemical superfractionator, and a steam stripper.

  1. Separation of alpha-, beta-, gamma-, delta-tocopherols and alpha-tocopherol acetate on a pentaerythritol diacrylate monostearate-ethylene dimethacrylate monolith by capillary electrochromatography.

    PubMed

    Chaisuwan, Patcharin; Nacapricha, Duangjai; Wilairat, Prapin; Jiang, Zhengjin; Smith, Norman W

    2008-06-01

    This work reports the first use of a monolith with method development for the separation of tocopherol (TOH) compounds by CEC with UV detection. A pentaerythritol diacrylate monostearate-ethylene dimethacrylate (PEDAS-EDMA) monolithic column has been investigated for an optimised condition to separate alpha-, beta-, gamma- and delta-TOHs, and alpha-tocopherol acetate (TAc). The PEDAS-EDMA monolith showed a remarkably good selectivity for separation of the TOH isomers including the beta- and gamma-isomers which are not easily separated by standard C8 or C18 particle-packed columns. Retention studies indicated that an RP mechanism was involved in the separation on the PEDAS-EDMA column, but polar interactions with the underlying ester and hydroxyl groups enhanced the separation of the problematic beta- and gamma-isomers. Separation of all the compounds was achieved within 25 min using 3:10:87 v/v/v 100 mM Tris buffer (pH 9.3)/methanol/ACN as the mobile phase. The method was successfully applied to a pharmaceutical sample with recoveries from 93 to 99%. Intraday and interday precisions (%RSD) for peak area and retention time were less than 2.3. LODs for all four TOHs and TAc were below 1 ppm.

  2. Catastrophic failure of a monolithic zirconia prosthesis.

    PubMed

    Chang, Jae-Seung; Ji, Woon; Choi, Chang-Hoon; Kim, Sunjai

    2015-02-01

    Recently, monolithic zirconia restorations have received attention as an alternative to zirconia veneered with feldspathic porcelain to eliminate chipping failures of veneer ceramics. In this clinical report, a patient with mandibular edentulism received 4 dental implants in the interforaminal area, and a screw-retained monolithic zirconia prosthesis was fabricated. The patient also received a maxillary complete removable dental prosthesis over 4 anterior roots. At the 18-month follow-up, all of the zirconia cylinders were seen to be fractured, and the contacting abutment surfaces had lost structural integrity. The damaged abutments were replaced with new abutments, and a new prosthesis was delivered with a computer-assisted design and computer-assisted manufacturing fabricated titanium framework with denture teeth and denture base resins. At the 6-month recall, the patient did not have any problems. Dental zirconia has excellent physical properties; however, care should be taken to prevent excessive stresses on the zirconia cylinders when a screw-retained zirconia restoration is planned as a definitive prosthesis.

  3. Monolithic Hydrogen Peroxide Catalyst Bed Development

    NASA Technical Reports Server (NTRS)

    Ponzo, J. B.

    2003-01-01

    With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

  4. Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G.

    PubMed

    de Lathouder, K M; Smeltink, M W; Straathof, A J J; Paasman, M A; van de Sandt, E J A X; Kapteijn, F; Moulijn, J A

    2008-08-01

    The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l(-1) PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml(-1) gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml(-1) gel. The observed volumetric reaction rate in the MLR was 0.79 mol s(-1) m(-3) (monolith). Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s(-1) m(-3) (catalyst)), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different reactor

  5. Column test-rig facility for column scanning studies

    NASA Astrophysics Data System (ADS)

    Zain, Rasif M.; Roslan, Y.

    2010-03-01

    Distillation columns are considered as one of the most critical components in oil and gas plants. The plant performance depends on the ability of these columns to function as intended. Defective columns may lead to serious consequences to the plant operation, and hence the quality of product. In order to perform any inspection techniques to distillation column for NDT practitioner, the best facility was designed when the adjustable defeats of distillation column test rig has been developed. The paper discussed the development and the function of this facility.

  6. Column test-rig facility for column scanning studies

    NASA Astrophysics Data System (ADS)

    Zain, Rasif M.; Roslan, Y.

    2009-12-01

    Distillation columns are considered as one of the most critical components in oil and gas plants. The plant performance depends on the ability of these columns to function as intended. Defective columns may lead to serious consequences to the plant operation, and hence the quality of product. In order to perform any inspection techniques to distillation column for NDT practitioner, the best facility was designed when the adjustable defeats of distillation column test rig has been developed. The paper discussed the development and the function of this facility.

  7. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... hydrogen chloride. The pure material occurs as hydroscopic, hexagonal, dark crystals. Ferric chloride... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... Specific Substances Affirmed as GRAS § 184.1297 Ferric chloride. (a) Ferric chloride (iron (III)...

  8. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride, FeC13, CAS Reg. No. 7705-08-0) may be prepared from iron and chlorine or from ferric oxide and hydrogen chloride. The pure... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric chloride. 184.1297 Section 184.1297...

  9. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... hydrogen chloride. The pure material occurs as hydroscopic, hexagonal, dark crystals. Ferric chloride... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... Specific Substances Affirmed as GRAS § 184.1297 Ferric chloride. (a) Ferric chloride (iron (III)...

  10. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... hydrogen chloride. The pure material occurs as hydroscopic, hexagonal, dark crystals. Ferric chloride... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... Specific Substances Affirmed as GRAS § 184.1297 Ferric chloride. (a) Ferric chloride (iron (III)...

  11. Benzalkonium Chloride and Glaucoma

    PubMed Central

    Kaufman, Paul L.; Kiland, Julie A.

    2014-01-01

    Abstract Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapoptosis, cytoskeleton changes, and immunoinflammatory reactions. These same effects have been reported in cultured human TM cells exposed to concentrations of BAK found in common glaucoma drugs and in the TM of primary open-angle glaucoma donor eyes. It is possible that a relationship exists between chronic exposure to BAK and glaucoma. The hypothesis that BAK causes/worsens glaucoma is being tested experimentally in an animal model that closely reflects human physiology. PMID:24205938

  12. Towards porous polymer monoliths for the efficient, retention-independent performance in the isocratic separation of small molecules by means of nano-liquid chromatography.

    PubMed

    Nischang, Ivo; Teasdale, Ian; Brüggemann, Oliver

    2010-11-26

    We have investigated the free-radical copolymerization dynamics of styrene and divinylbenzene in the presence of micro- and macro-porogenic diluents in 100 μm I.D. sized molds under conditions of slow thermal initiation leading to (macro)porous poly(styrene-co-divinylbenzene) monolithic scaffolds. These specifically designed experiments allowed the quantitative determination of monomer specific conversion against polymerization time to derive the porous polymer scaffold composition at each desirable copolymerization stage after phase separation. This was carried out over a time scale of 3h up to 48 h polymerization time, enabling the efficient and repeatable termination of the polymerization reactions. In parallel, the porous and hydrodynamic properties of the derived monolithic columns were thoroughly studied in isocratic nano-LC mode for the reversed-phase separation of a homologous series of small retained molecules. At the optimized initiator concentration, polymerization temperature and time, the macroporous poly(styrene-co-divinylbenzene) monoliths show a permanent mesoporous pore space, which was readily observable by electron microscopy and indicated by nitrogen adsorption experiments. Under these conditions, we consistently find a polymer scaffold composition which suggests a high degree of cross-linking and thus minimum amount of gel porosity. These columns reveal a retention-insensitive plate height in the separation of small retained molecules which only slightly decreases at increased linear mobile phase velocity. As the polymerization progresses, a build-up of less-densely cross-linked material occurs, which is directly reflected in the observed consistent increase in retention and plate heights. This leads to a significant deterioration in overall isocratic separation performance. The decrease in performance is ascribed in particular to the increased mass transfer resistance governing the monoliths' performance over the whole linear chromatographic

  13. REMOVAL OF IODIDE FROM GROUNDWATER USING SILVER CHLORIDE WHITE PAPER

    SciTech Connect

    Johns, M

    2008-11-26

    Releases from the F and H Area Seepage Basins on the Savannah River Site (SRS) have caused groundwater plumes that contain a variety of contaminants. These plumes are releasing contaminants into Fourmile Branch, which is a small tributary of the Savannah River. The metallic contaminant releases to the branch are being controlled by base injection. The base injection targets cationic contaminants and was not intended to reduce the concentration of I-129 in groundwater. SRS and the regulatory agencies believe it is appropriate to investigate remedial alternatives that could reduce the I-129. The Savannah River Site Area Closures Projects (ACP) and the Savannah River National Laboratory (SRNL) are developing an innovative in situ treatment for I-129 using silver chloride (AgCl). The proposed AgCl amendment has a very small particle size and is designed to be injected into the contaminated aquifer to capture I-129. The solubility of AgI is several orders of magnitude lower than the solubility of AgCl. Thus, when I-129 comes in contact with AgCl it forms silver iodide (AgI), which is very stable and essentially insoluble in water. SRNL has been performing bench-scale column tests on the effectiveness of silver chloride to capture iodine in an aqueous solution. These initial tests evaluate silver chloride in four different particle sizes; 4-5 millimeters (standard reagent silver chloride), approximately 1 millimeters (sieved reagent silver chloride), approximately 2 micrometers (ultra fine grind without a grinding agent), and <1 micrometer (ultra fine grind with a grinding agent). The first two experiments with macro-sized particles were proof of principle tests. In these the AgCl was mechanically mixed into a portion of the soil filling the columns. The last two were to test the effectiveness of injecting particles suspended in an aqueous solution--the ability to inject the particles, their retention in the column and their effectiveness at removing dissolved iodide

  14. Single-step approach for fabrication of vancomycin-bonded silica monolith as chiral stationary phase.

    PubMed

    Hsieh, Ming-Lung; Chau, Lai-Kwan; Hon, Yung-Son

    2014-09-01

    A vancomycin-bonded silica monolithic column for capillary electrochromatography (CEC) was prepared by a single-step in situ sol-gel approach. This sol-gel process incorporates a synthetic sol-gel precursor which contains a macrocyclic antibiotic, vancomycin, to form a porous silica network inside a fused-silica capillary. To avoid degradation of vancomycin during the column fabrication, a mild step was adopted into the sol-gel process. The performance of the vancomycin chiral stationary phase was investigated by CEC in both the reversed-phase mode and the normal-phase mode. The vancomycin chiral stationary phase was optimized with respect to vancomycin loading in the reversed-phase mode for chiral separation of thalidomide enantiomers. The best efficiency and resolution values of 94600plates/m and 5.79, respectively, were achieved. The optimized column was further applied to chiral separation of alprenolol enantiomers. A plate height of less than 7μm for the first eluted enantiomer of alprenolol was obtained in an aqueous mobile phase at a flow rate of 0.74mm/s. Using enantiomers of seven β-blockers and some other basic enantiomers as test analytes, separation efficiencies of up to 148100plates/m in the reversed-phase mode and up to 138100plates/m in the normal-phase mode were achieved.

  15. Rapid process for producing transparent, monolithic porous glass

    DOEpatents

    Coronado, Paul R.

    2006-02-14

    A process for making transparent porous glass monoliths from gels. The glass is produced much faster and in much larger sizes than present technology for making porous glass. The process reduces the cost of making large porous glass monoliths because: 1) the process does not require solvent exchange nor additives to the gel to increase the drying rates, 2) only moderate temperatures and pressures are used so relatively inexpensive equipment is needed, an 3) net-shape glass monoliths are possible using this process. The process depends on the use of temperature to control the partial pressure of the gel solvent in a closed vessel, resulting in controlled shrinking during drying.

  16. A decoupled monolithic projection method for natural convection problems

    NASA Astrophysics Data System (ADS)

    Pan, Xiaomin; Kim, Kyoungyoun; Lee, Changhoon; Choi, Jung-Il

    2016-06-01

    We propose an efficient monolithic numerical procedure based on a projection method for solving natural convection problems. In the present monolithic method, the buoyancy, linear diffusion, and nonlinear convection terms are implicitly advanced by applying the Crank-Nicolson scheme in time. To avoid an otherwise inevitable iterative procedure in solving the monolithic discretized system, we use a linearization of the nonlinear convection terms and approximate block lower-upper (LU) decompositions along with approximate factorization. Numerical simulations demonstrate that the proposed method is more stable and computationally efficient than other semi-implicit methods, preserving temporal second-order accuracy.

  17. Phosphatidylcholine covalently linked to a methacrylate-based monolith as a biomimetic stationary phase for capillary liquid chromatography.

    PubMed

    Moravcová, Dana; Carrasco-Correa, Enrique Javier; Planeta, Josef; Lämmerhofer, Michael; Wiedmer, Susanne K

    2015-07-10

    In this study a strategy to immobilize phospholipids onto a polymer-based stationary phase is described. Methacrylate-based monoliths in capillary format (150×0.1mm) were modified by soybean phosphatidylcholine through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide coupling to obtain stationary phases suitable to mimic cell surface membranes. The covalent coupling reaction involves the phosphate group in phospholipids; therefore, the described methodology is suitable for all types of phospholipids. Immobilization of soy bean phosphatidylcholine on the monolith was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry of the fatty alcohol profile, generated upon reductive cleavage of the fatty acyl side chains of the phospholipid on the monolith surface with lithium aluminium hydride. The prepared stationary phases were evaluated through studies on the retention of low-molar mass model analytes including neutral, acidic, and basic compounds. Liquid chromatographic studies confirmed predominant hydrophobic interactions between the analytes and the synthesized stationary phase; however, electrostatic interactions contributed to the retention as well. The synthesized columns showed high stability even with fully aqueous mobile phases such as Dulbecco's phosphate-buffered saline solution.

  18. Transport and distribution of Salmonella enterica serovar Typhimurium in loamy and sandy soil monoliths with applied liquid manure.

    PubMed

    Bech, Tina B; Johnsen, Kaare; Dalsgaard, Anders; Laegdsmand, Mette; Jacobsen, Ole Hørbye; Jacobsen, Carsten S

    2010-02-01

    A leaching experiment, where liquid manure spiked with Salmonella enterica serovar Typhimurium (Tet(+)) DSM554 was applied to soil surfaces, was conducted on intact soil monoliths (60 cm in diameter and 100 cm long). A total of 6.5 x 10(10) CFU was applied to each column. We found that Salmonella serovar Typhimurium could be transported to a 1-m depth in loamy soil at concentrations reaching 1.3 x 10(5) CFU/ml of leachate. The test strain was found in concentrations ranging from 300 to 1.3(5) cells/ml in loamy soil throughout the 27 days of the experiment, while concentrations below 20 cells/ml were sporadically detected in the leachates from sandy monoliths. Real-time PCR targeting invA DNA showed a clear correspondence between the total and culturable numbers of cells in the leachate, indicating that most cells leached were viable. On day 28, distribution of Salmonella serovar Typhimurium at five depths in the four monoliths was determined. The highest recovery rate, ranging from 1.5% to 3.8% of the total applied inoculum, was found in the top 0.2 m.

  19. Phosphatidylcholine covalently linked to a methacrylate-based monolith as a biomimetic stationary phase for capillary liquid chromatography.

    PubMed

    Moravcová, Dana; Carrasco-Correa, Enrique Javier; Planeta, Josef; Lämmerhofer, Michael; Wiedmer, Susanne K

    2015-07-10

    In this study a strategy to immobilize phospholipids onto a polymer-based stationary phase is described. Methacrylate-based monoliths in capillary format (150×0.1mm) were modified by soybean phosphatidylcholine through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide coupling to obtain stationary phases suitable to mimic cell surface membranes. The covalent coupling reaction involves the phosphate group in phospholipids; therefore, the described methodology is suitable for all types of phospholipids. Immobilization of soy bean phosphatidylcholine on the monolith was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry of the fatty alcohol profile, generated upon reductive cleavage of the fatty acyl side chains of the phospholipid on the monolith surface with lithium aluminium hydride. The prepared stationary phases were evaluated through studies on the retention of low-molar mass model analytes including neutral, acidic, and basic compounds. Liquid chromatographic studies confirmed predominant hydrophobic interactions between the analytes and the synthesized stationary phase; however, electrostatic interactions contributed to the retention as well. The synthesized columns showed high stability even with fully aqueous mobile phases such as Dulbecco's phosphate-buffered saline solution. PMID:26024990

  20. Neutral, Charged and Stratified Polar Monoliths for Hydrophilic Interaction Capillary Electrochromatography

    PubMed Central

    Gunasena, Dilani N.; El Rassi, Ziad

    2013-01-01

    Novel polar monoliths were introduced for hydrophilic interaction capillary electrochromatography (HI-CEC). In one case, a neutral polar monolith resulted from the in situ polymerization of glyceryl methacrylate (GMM) and pentaerythritol triacrylate (PETA) in a ternary porogenic solvent. GMM and PETA possess hydroxyl functional groups, which impart the monolith with hydrophilic interaction sites. This monolith is designated as hydroxy monolith. Although the hydroxy monolith is neutral and void of fixed charges on the surface, a relatively strong cathodal EOF was observed due to the electric double layer formed by the adsorption of ions from the mobile phase, producing a bulk mobile phase flow. The second monolith is charged and referred to as AP-monolith that possesses amine/amide functionalities on its surface, and was prepared by the in situ polymerization of N-(3-aminopropyl) methacrylamide hydrochloride (NAPM) and ethylene dimethacrylate (EDMA) in the presence of cyclohexanol, dodecanol and methanol as porogens. Over the pH range studied a strong anodal EOF was observed. The AP-monolith was further exploited in HI-CEC by modifying its surface with neutral mono- and oligosaccharides to produce a series of the so called sugar modified AP-monoliths (SMAP-monolith), which are considered as stratified hydrophilic monoliths possessing a sub-layer of polar amine/amide groups and a top layer of sugar (a polyhydroxy top layer).The SMAP-monoliths can be viewed as a blend of both the hydroxy monolith and the AP-monolith. The polarity of the various monoliths seems to follow the order: hydroxy monolith < AP-monolith < SMAP-monolith. The novel monoliths were characterized over a wide range of elution conditions with a variety of polar solutes including phenols, substituted phenols, nucleic acid bases, nucleosides and nucleotides PMID:23972465

  1. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K.; Wei, G.; Yu, P.C.

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  2. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. . Electro-Optics Technology Center); Wei, G. ); Yu, P.C. )

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  3. The Advanced Virgo monolithic fused silica suspension

    NASA Astrophysics Data System (ADS)

    Aisa, D.; Aisa, S.; Campeggi, C.; Colombini, M.; Conte, A.; Farnesini, L.; Majorana, E.; Mezzani, F.; Montani, M.; Naticchioni, L.; Perciballi, M.; Piergiovanni, F.; Piluso, A.; Puppo, P.; Rapagnani, P.; Travasso, F.; Vicerè, A.; Vocca, H.

    2016-07-01

    The detection of gravitational waves is one of the most challenging prospects faced by experimental physicists. Suspension thermal noise is an important noise source at operating frequencies between approximately 10 and 30 Hz, and represents a limit to the sensitivity of the ground based interferometric gravitational wave detectors. Its effects can be reduced by minimizing the losses and by optimizing the geometry of the suspension fiber as well as its attachment system. In this proceeding we will describe the mirrors double stage monolithic suspension system to be used in the Advanced Virgo (AdV) detector. We also present the results of the thermal noise study, performed with the help of a finite elements model, taking into account the precise geometry of the fibers attachment systems on the suspension elements. We shall demonstrate the suitability of this suspension for installation in AdV.

  4. Monolithic short wave infrared (SWIR) detector array

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

  5. Monolithic fuel injector and related manufacturing method

    DOEpatents

    Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin; York, William David; Stevenson, Christian Xavier

    2012-05-22

    A monolithic fuel injection head for a fuel nozzle includes a substantially hollow vesicle body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween, an internal baffle plate extending radially outwardly from a downstream end of the bore, terminating short of the peripheral wall, thereby defining upstream and downstream fuel plenums in the vesicle body, in fluid communication by way of a radial gap between the baffle plate and the peripheral wall. A plurality of integral pre-mix tubes extend axially through the upstream and downstream fuel plenums in the vesicle body and through the baffle plate, with at least one fuel injection hole extending between each of the pre-mix tubes and the upstream fuel plenum, thereby enabling fuel in the upstream plenum to be injected into the plurality of pre-mix tubes. The fuel injection head is formed by direct metal laser sintering.

  6. Monolithically Peltier-cooled laser diodes

    NASA Astrophysics Data System (ADS)

    Hava, S.; Hunsperger, R. G.; Sequeira, H. B.

    1984-04-01

    A new method of cooling a GaAs/GaAlAs laser in an optical integrated circuit or on a discrete chip, by adding an integral thermoelectric (Peltier) cooling and heat spreading device to the laser, is presented. This cooling both reduces and stabilizes the laser junction temperature to minimize such deleterious effects as wavelength drift due to heating. A unified description of the electrical and thermal properties of a monolithic semiconductor mesa structure is given. Here it is shown that an improvement in thermal characteristics is obtained by depositing a relatively thick metallic layer, and by using this layer as a part of an active Peltier structure. Experimental results reveal a 14-percent increase in emitted power (external quantum efficiency) due to passive heat spreading and a further 8-percent if its Peltier cooler is operated. Fabrication techniques used to obtain devices exhibiting the above performance characteristics are given.

  7. Monolithically Peltier-cooled laser diodes

    SciTech Connect

    Hava, S.; Hunsperger, R.G.; Sequeira, H.B.

    1984-04-01

    A new method of cooling a GaAs/GaAlAs laser in an optical integrated circuit or on a discrete chip, by adding an integral thermoelectric (Peltier) cooling and heat spreading device to the laser, is presented. This cooling both reduces and stabilizes the laser junction temperature to minimize such deleterious effects as wavelength drift due to heating. A unified description of the electrical and thermal properties of a monolithic semiconductor mesa structure is given. Here it is shown that an improvement in thermal characteristics is obtained by depositing a relatively thick metallic layer, and by using this layer as a part of an active Peltier structure. Experimental results reveal a 14-percent increase in emitted power (external quantum efficiency) due to passive heat spreading and a further 8-percent if its Peltier cooler is operated. Fabrication techniques used to obtain devices exhibiting the above performance characteristics are given. 21 references.

  8. Monolithic microwave integrated circuit water vapor radiometer

    NASA Technical Reports Server (NTRS)

    Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

    1991-01-01

    A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

  9. Transparent monolithic metal ion containing nanophase aerogels

    SciTech Connect

    Risen, W. M., Jr.; Hu, X.; Ji, S.; Littrell, K.

    1999-12-01

    The formation of monolithic and transparent transition metal containing aerogels has been achieved through cooperative interactions of high molecular weight functionalized carbohydrates and silica precursors, which strongly influence the kinetics of gelation. After initial gelation, subsequent modification of the ligating character of the system, coordination of the group VIII metal ions, and supercritical extraction afford the aerogels. The structures at the nanophase level have been probed by photon and electron transmission and neutron scattering techniques to help elucidate the basis for structural integrity together with the small entity sizes that permit transparency in the visible range. They also help with understanding the chemical reactivities of the metal-containing sites in these very high surface area materials. These results are discussed in connection with new reaction studies.

  10. Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.

    PubMed

    Shih, Yung-Han; Lirio, Stephen; Li, Chih-Keng; Liu, Wan-Ling; Huang, Hsi-Ya

    2016-01-01

    In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives.

  11. Reactor-chromatographic determination of vinyl chloride in polyvinyl chloride

    SciTech Connect

    Berezkin, V.G.

    1986-08-01

    The authors carry out a chromatographic study of the volatile products that evolve when various grades of domestic polyvinyl chloride are heated, to determine the concentration of residual monomer. To find vinyl chloride in complex mixtures of air pollutants the authors used sorptive reaction concentration of impurities. This new combination of methods is based on preliminary separation at the sampling stage of impurities that interfere in the analysis, followed by concentration of the desired components in a trap with an adsorbent, and chromatographic determination of the concentrated trace materials. The method obtains low vinyl chloride concentrations (down to 10/sup -4/-10/sup -5/ wt. %) with +/-5 relative error.

  12. Advances in monoliths and related porous materials for microfluidics.

    PubMed

    Knob, Radim; Sahore, Vishal; Sonker, Mukul; Woolley, Adam T

    2016-05-01

    In recent years, the use of monolithic porous polymers has seen significant growth. These materials present a highly useful support for various analytical and biochemical applications. Since their introduction, various approaches have been introduced to produce monoliths in a broad range of materials. Simple preparation has enabled their easy implementation in microchannels, extending the range of applications where microfluidics can be successfully utilized. This review summarizes progress regarding monoliths and related porous materials in the field of microfluidics between 2010 and 2015. Recent developments in monolith preparation, solid-phase extraction, separations, and catalysis are critically discussed. Finally, a brief overview of the use of these porous materials for analysis of subcellular and larger structures is given. PMID:27190564

  13. 62. VIEW SHOWING INSTALLATION TAINTER VALVE MACHINERY MONOLITH NO. 321, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. VIEW SHOWING INSTALLATION TAINTER VALVE MACHINERY MONOLITH NO. 32-1, LOOKING WEST Photograph No. 8571. October 24, 1949 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  14. 10. LOCK CONSTRUCTION PHOTO SHOWING CONCRETE MONOLITHS FOR WALLS, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LOCK CONSTRUCTION PHOTO SHOWING CONCRETE MONOLITHS FOR WALLS, LOOKING NORTH. August 1934 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 16, Upper Mississippi River, Muscatine, Muscatine County, IA

  15. 25. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END OF MAIN LOCK AND DAM PIERS, LOOKING SOUTHEAST (DOWNSTREAM). NOTE GANTRY CRANES - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  16. 53. VIEW OF ROCK FOUNDATIONS AIR CLEANED FOR MONOLITHS 1722, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. VIEW OF ROCK FOUNDATIONS AIR CLEANED FOR MONOLITHS 17-22, INTERMEDIATE WALL, LOOKING NORTH Photograph No. 12840. September 10, 1948 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  17. 27. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT DOWNSTREAM END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT DOWNSTREAM END OF WEST MAIN LOCK WALL, LOOKiNG SOUTHEAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  18. 26. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END OF MAIN LOCK AND DAM PIERS, LOOKING SOUTHEAST (DOWNSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  19. Experimental and computational investigation of flow in catalytic monolith channels

    SciTech Connect

    Wilson, G.C.; Bardon, M.F.; Witton, J.J. Cranfield Inst. of Technology )

    1992-01-01

    Monolith optimization is necessary for maximum efficiency during catalytic combustion. This paper describes a study undertaken to investigate the flow in catalytic monolith channels. A super-scale model of a single passage in a ceramic catalyst monolith was constructed and studied using pure air as the working fluid. Combustion of a representative natural gas mixture at the catalyst surface was simulated by electrical heating of the channel walls. The flow-field was probed with hot wire anemometers and fine wire thermocouples to obtain velocity and temperature data. Concurrently, the PHOENICS CFD package was used to model the flow. Results confirmed the presence of secondary flows and illustrated the effects of channel shape. The results are discussed as to their relevance to the design of a monolithic combustor for gas turbine applications. 15 refs.

  20. 31. SPILLWAY CHANNEL WALLS REINF DETAILS; MONOLITHS E21 AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. SPILLWAY CHANNEL WALLS REINF - DETAILS; MONOLITHS E-21 AND W-21. Sheet S-45, May, 1940. File no. 342/58. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  1. Enantiomer separation of acidic chiral compounds on a quinine-silica/zirconia hybrid monolith by capillary electrochromatography.

    PubMed

    Tran, Le Ngoc; Park, Jung Hag

    2015-05-29

    A weak anion-exchanger chiral selector, quinine-incorporated silica/zirconia hybrid monolithic (QUI-S/ZHM) capillary column was prepared by sol-gel technology. The performance of the QUI-S/ZHM column was investigated for enantioresolution of a set of acidic chiral drugs and dinitrobenzoyl (DNB)-amino acids by capillary electrochromatography in aqueous organic mobile phases composed of acetonitrile (ACN) and triethylammonium acetate (TEAA) buffer. Effects of several parameters including the ACN content, concentration and pH of the mobile phase on the chiral separation were examined. Baseline resolutions of all the compounds were obtained in the mobile phase consisting of 70:30 ACN/TEAA (10mM, pH 6) under applied voltage of -10kV at 25°C within 20min.

  2. SPIRAL CONTACTOR FOR SOLVENT EXTRACTION COLUMN

    DOEpatents

    Cooley, C.R.

    1961-06-13

    The patented extraction apparatus includes a column, perforated plates extending across the column, liquid pulse means connected to the column, and an imperforate spiral ribbon along the length of the column.

  3. Why Hexagonal Basalt Columns?

    PubMed

    Hofmann, Martin; Anderssohn, Robert; Bahr, Hans-Achim; Weiß, Hans-Jürgen; Nellesen, Jens

    2015-10-01

    Basalt columns with their preferably hexagonal cross sections are a fascinating example of pattern formation by crack propagation. Junctions of three propagating crack faces rearrange such that the initial right angles between them tend to approach 120°, which enables the cracks to form a pattern of regular hexagons. To promote understanding of the path on which the ideal configuration can be reached, two periodically repeatable models are presented here involving linear elastic fracture mechanics and applying the principle of maximum energy release rate. They describe the evolution of the crack pattern as a transition from rectangular start configuration to the hexagonal pattern. This is done analytically and by means of three-dimensional finite element simulation. The latter technique reproduces the curved crack path involved in this transition.

  4. Why Hexagonal Basalt Columns?

    PubMed

    Hofmann, Martin; Anderssohn, Robert; Bahr, Hans-Achim; Weiß, Hans-Jürgen; Nellesen, Jens

    2015-10-01

    Basalt columns with their preferably hexagonal cross sections are a fascinating example of pattern formation by crack propagation. Junctions of three propagating crack faces rearrange such that the initial right angles between them tend to approach 120°, which enables the cracks to form a pattern of regular hexagons. To promote understanding of the path on which the ideal configuration can be reached, two periodically repeatable models are presented here involving linear elastic fracture mechanics and applying the principle of maximum energy release rate. They describe the evolution of the crack pattern as a transition from rectangular start configuration to the hexagonal pattern. This is done analytically and by means of three-dimensional finite element simulation. The latter technique reproduces the curved crack path involved in this transition. PMID:26550724

  5. Finite element analysis of monolithic solid oxide fuel cells

    SciTech Connect

    Saigal, A. . Dept. of Mechanical Engineering); Majumdar, S. )

    1992-01-01

    This paper investigates the stress and fracture behavior of a monolithic solid oxide fuel cell (MSOFC) currently under joint development by Allied Signal Corporation and Argonne National Laboratory. The MSOFC is an all-ceramic fuel cell capable of high power density and tolerant of a variety of hydrocarbon fuels, making it potentially attractive for stationary utility and mobile transportation systems. The monolithic design eliminates inactive structural supports, increases active surface area, and lowers voltage losses caused by internal resistance.

  6. Finite element analysis of monolithic solid oxide fuel cells

    SciTech Connect

    Saigal, A.; Majumdar, S.

    1992-04-01

    This paper investigates the stress and fracture behavior of a monolithic solid oxide fuel cell (MSOFC) currently under joint development by Allied Signal Corporation and Argonne National Laboratory. The MSOFC is an all-ceramic fuel cell capable of high power density and tolerant of a variety of hydrocarbon fuels, making it potentially attractive for stationary utility and mobile transportation systems. The monolithic design eliminates inactive structural supports, increases active surface area, and lowers voltage losses caused by internal resistance.

  7. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    SciTech Connect

    Serne, R. Jeffrey; Westsik, Joseph H.; Williams, Benjamin D.; Jung, H. B.; Wang, Guohui

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  8. Preparation of a pipette tip-based molecularly imprinted solid-phase microextraction monolith by epitope approach and its application for determination of enkephalins in human cerebrospinal fluid.

    PubMed

    Li, Hua; Li, Dan

    2015-11-10

    In this study, a novel molecularly imprinted polymer (MIP) monolith for highly selective extraction of enkephalins was synthesized and prepared in a micropipette tip using epitope imprinting technique. The synthesized MIPs were characterized by scanning electron microscope (SEM) and infrared spectroscopy. A molecularly imprinted solid-phase microextraction (MISPME) method was developed for extraction of enkephalins in aqueous solutions. The parameters affecting MISPME were optimized. The results indicated that this MIP monolith exhibited specific recognition capability, high enrichment efficiency and excellent reusability for enkephalins. MALDI-TOF MS analysis demonstrated that this MIP monolith can act as a useful tool for highly selective purification and enrichment of enkephalin, a kind of low abundance protein, from high-abundance proteins in human cerebrospinal fluids (CSF). Employed this MIP monolith as solid-phase microextraction column, quantitative assay of enkephalins in human CSF was developed by HPLC-ultraviolet (UV) detection in this work. The detection limits were 0.05-0.08nM. This MISPME/HPLC-UV method was used to quantify Met-enkephalin and Leu-enkephalin levels in the CSF of patients with cancer pain.

  9. Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

    PubMed

    Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

    2015-02-28

    The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors. PMID:25572361

  10. Direct conversion of silver complexes to nanoscale hexagonal columns on a copper alloy for plasmonic applications.

    PubMed

    Yamamoto, Yuko S; Hasegawa, Katsuyuki; Hasegawa, Yuuki; Takahashi, Naoshi; Kitahama, Yasutaka; Fukuoka, Satoshi; Murase, Norio; Baba, Yoshinobu; Ozaki, Yukihiro; Itoh, Tamitake

    2013-09-21

    We introduced a novel method for the rapid synthesis of silver nanohexagonal thin columns from an aqueous mixture of sodium thiosulfate (Na2S2O3) and silver chloride (AgCl) simply added to a phosphor bronze substrate. The reaction is based on galvanic displacement and the products are potentially useful for plasmonic applications.

  11. Characterization of methacrylate chromatographic monoliths bearing affinity ligands.

    PubMed

    Černigoj, Urh; Vidic, Urška; Nemec, Blaž; Gašperšič, Jernej; Vidič, Jana; Lendero Krajnc, Nika; Štrancar, Aleš; Podgornik, Aleš

    2016-09-16

    We investigated effect of immobilization procedure and monolith structure on chromatographic performance of methacrylate monoliths bearing affinity ligands. Monoliths of different pore size and various affinity ligands were prepared and characterized using physical and chromatographic methods. When testing protein A monoliths with different protein A ligand densities, a significant nonlinear effect of ligand density on dynamic binding capacity (DBC) for IgG was obtained and accurately described by Langmuir isotherm curve enabling estimation of protein A utilization as a function of ligand density. Maximal IgG binding capacity was found to be at least 12mg/mL exceeding theoretical monolayer adsorption value of 7.8mg/mL assuming hexagonal packing and IgG hydrodynamic diameter of 11nm. Observed discrepancy was explained by shrinkage of IgG during adsorption on protein A experimentally determined through calculated adsorbed IgG layer thickness of 5.4nm from pressure drop data. For monoliths with different pore size maximal immobilized densities of protein A as well as IgG dynamic capacity linearly correlates with monolith surface area indicating constant ligand utilization. Finally, IgGs toward different plasma proteins were immobilized via the hydrazide coupling chemistry to provide oriented immobilization. DBC was found to be flow independent and was increasing with the size of bound protein. Despite DBC was lower than IgG capacity to immobilized protein A, ligand utilization was higher. PMID:27554023

  12. Buckling of a holey column.

    PubMed

    Pihler-Puzović, D; Hazel, A L; Mullin, T

    2016-09-14

    We report the results from a combined experimental and numerical investigation of buckling in a novel variant of an elastic column under axial load. We find that including a regular line of centred holes in the column can prevent conventional, global, lateral buckling. Instead, the local microstructure introduced by the holes allows the column to buckle in an entirely different, internal, mode in which the holes are compressed in alternate directions, but the column maintains the lateral reflection symmetry about its centreline. The internal buckling mode can be accommodated within a smaller external space than the global one; and it is the preferred buckling mode over an intermediate range of column lengths for sufficiently large holes. For very short or sufficiently long columns a modification of the classical, global, lateral buckling is dominant. PMID:27501288

  13. Studies Update Vinyl Chloride Hazards.

    ERIC Educational Resources Information Center

    Rawls, Rebecca

    1980-01-01

    Extensive study affirms that vinyl chloride is a potent animal carcinogen. Epidemiological studies show elevated rates of human cancers in association with extended contact with the compound. (Author/RE)

  14. Single-walled carbon nanotube-based polymer monoliths for the enantioselective nano-liquid chromatographic separation of racemic pharmaceuticals.

    PubMed

    Ahmed, Marwa; Yajadda, Mir Massoud Aghili; Han, Zhao Jun; Su, Dawei; Wang, Guoxiu; Ostrikov, Kostya Ken; Ghanem, Ashraf

    2014-09-19

    Single-walled carbon nanotubes were encapsulated into different polymer-based monolithic backbones. The polymer monoliths were prepared via the copolymerization of 20% monomers, glycidyl methacrylate, 20% ethylene glycol dimethacrylate and 60% porogens (36% 1-propanol, 18% 1,4-butanediol) or 16.4% monomers (16% butyl methacrylate, 0.4% sulfopropyl methacrylate), 23.6% ethylene glycol dimethacrylate and 60% porogens (36% 1-propanol, 18% 1,4-butanediol) along with 6% single-walled carbon nanotubes aqueous suspension. The effect of single-walled carbon nanotubes on the chiral separation of twelve classes of pharmaceutical racemates namely; α- and β-blockers, antiinflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs and antiarrhythmic drugs was investigated. The enantioselective separation was carried out under multimodal elution to explore the chiral recognition capabilities of single-walled carbon nanotubes using reversed phase, polar organic and normal phase chromatographic conditions using nano-liquid chromatography. Baseline separation was achieved for celiprolol, chlorpheniramine, etozoline, nomifensine and sulconazole under multimodal elution conditions. Satisfactory repeatability was achieved through run-to-run, column-to-column and batch-to-batch investigations. Our findings demonstrate that single-walled carbon nanotubes represent a promising stationary phase for the chiral separation and may open the field for a new class of chiral selectors.

  15. Compact electron beam focusing column

    SciTech Connect

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-07-13

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  16. Aluminum based metal-organic framework-polymer monolith in solid-phase microextraction of penicillins in river water and milk samples.

    PubMed

    Lirio, Stephen; Liu, Wan-Ling; Lin, Chen-Lan; Lin, Chia-Her; Huang, Hsi-Ya

    2016-01-01

    In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200μL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (<3.4% RSDs) while 88.5-90.5% (<5.8% RSDs) for batch-to-batch (n=3). Under the optimal conditions, the limit of detections were in the range of 0.06-0.26μgL(-1) and limit of quantifications between 0.20 and 0.87

  17. Aluminum based metal-organic framework-polymer monolith in solid-phase microextraction of penicillins in river water and milk samples.

    PubMed

    Lirio, Stephen; Liu, Wan-Ling; Lin, Chen-Lan; Lin, Chia-Her; Huang, Hsi-Ya

    2016-01-01

    In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200μL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (<3.4% RSDs) while 88.5-90.5% (<5.8% RSDs) for batch-to-batch (n=3). Under the optimal conditions, the limit of detections were in the range of 0.06-0.26μgL(-1) and limit of quantifications between 0.20 and 0.87

  18. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns.

    PubMed

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity. PMID:23697993

  19. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns

    NASA Astrophysics Data System (ADS)

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~ 75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity.

  20. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns.

    PubMed

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity.